As recently demonstrated, the group of Adiantum raddianum is monophyletic and can be recognized by round-reniform indusia and veins ending in sinuses at the sterile segment margins. The most related species belong to the A. poiretii group, which is morphologically distinct by the oblong to lunate indusia. In the A. raddianum group sixteen species are recognized in the present work. Among these species, A. patens s.l. is the unique species that occurs in Africa outside the neotropical region. Adiantum raddianum is the broadest distributed species of the group, widely cultivated globally, and it has become naturalized in the Paleotropics and other regions. Typifications are presented for two accepted names: A. lorentzii and A. ruizianum. Several other typifications are also presented for synonymized species. Adiantum alan-smithii, A. galeottianum, A. imbricatum, A. lobatum, A. ruizianum, A. shepherdii and A. subvolubile are species with restricted distributions occurring only in one or two countries. An identification key, as well as descriptions, synonymies, discussion on morphology and taxonomy, illustrations and a list of specimens examined are provided.
Citation: Hirai R. Y. & Prado J. 2019: Neotropical species of the Adiantum raddianum group (Pteridaceae). – Willdenowia 49: 295–317. doi: https://doi.org/10.3372/wi.49.49302
Version of record first published online on 26 November 2019 ahead of inclusion in December 2019 issue.
Introduction
Adiantum L., commonly known as the maidenhair ferns, belongs to the Pteridaceae, a family with c. 50 genera and 950 species (Smith & al. 2006, 2008). More recently, PPG I (2016) accept 53 genera and an estimated 1211 species. A recent paper about the genus, Kessler & al. (2017) estimates c. 225 species, widely distributed from cold temperatures to tropics, most of them occurring in the neotropical region (Mickel & Smith 2004; Lin & al. 2013). In the last years, several new species of Adiantum have been described increasing the size of the genus (e.g. Prado 2000, 2001, 2003, 2005, 2006; Lellinger & Prado 2001; Prado & Smith 2002; Smith & Prado 2004; Sundue & Prado 2005; Zimmer 2007; Caluff 2009; Sundue & al. 2010; McCarthy & Hickey 2011; Prado & Hirai 2013; Hirai & al. 2014; Huiet & al. 2015; Boudrie & al. 2017; Prado & al. 2017).
Tryon & Tryon (1982) in Ferns and allied plants, with special reference to tropical America treated Adiantum in eight informal groups mainly based in the division of the lamina (simple to 1–6-pinnate), the pattern of venation (free or anastomosing), and indument of axes (hairs and scales): (1) A. capillus-veneris L. (including species such as A. concinnum Willd., A. orbignyanum Kuhn, A. poiretii Wikstr., A. raddianum C. Presl and A. subvolubile Kuhn); (2) A. patens Willd. (including species such as A. oatesii Baker, A. ruizianum Klotzsch, A. sessilifolium Hook., A. shepherdii Hook., A. galeottianum Hook., A. lobatum C. Presl and A. sinuosum Gardner); (3) A. pectinatum Kunze ex Baker; (4) A. philippense L.; (5) A. phyllitidis J. Sm.; (6) A. platyphyllum Sw.; (7) A. reniforme L.; and (8) A. tetraphyllum Humb. & Bonpl. ex Willd.
Hirai & al. (2016) delimited the species that belong to the Adiantum raddianum group based on molecular and morphological data. Molecularly this group can be recognized by having a unique 66 nucleotide insertion in the chlN gene alignment, morphologically by pseudopedate to 1–5-pinnate laminae, sterile segments with veins ending in sinuses at the segment margins and round-reniform sori. They used five chloroplast markers (atpA, rbcL, chlL, chlN, rpoA) and showed that the A. poiretti group is sister to A. raddianum group. The species now recognized in the A. raddianum group had been placed by Tryon & Tryon (1982) in either the A. capillus-veneris or A. patens groups. The group of A. capillus-veneris was characterized by Tryon & Tryon (1982) in having lamina 2–4-pinnate, gradually reduced to the apex, rachises glabrous, segments flabellate to flabellate-cuneate, short to long-stalked, few to several indusia, and veins free; and the group of A. patens in having lamina 1–3-pinnate or helicoid, rachises glabrous or pubescent, segments flabellate to flabellate-cuneate, sessile to short-stalked, few to several indusia, and veins free (Tryon & Tryon 1982).
Huiet & al. (2018), addressed a global study for the genus Adiantum, corroborated the monophyletism of the A. raddianum group (sensu Hirai & al. 2016) and positioned it in a larger clade called the formosum clade. In total, they recovered nine monophyletic lineages into Adiantum, which they called digitatum, formosum, tenerum, pedatum, capillus-veneris, davidii, philippense, peruvianum and tetraphyllum. This paper by Huiet & al. (2018) revealed that the lamina division is a character notably convergent, but it associated with other characters can be used to support groups. For example, the species belong to the phillipense clade have leaves 1-pinnate and usually with proliferous rachises at the apex. The lineage of A. philippense had been recognized as a distinct group in previous classifications, for example in Tryon & Tryon (1982). Biogeographically, 75% (146 spp.) of the studied species of the genus belong to one of six biogeographical regions (Eurasia, Australasia, Africa, South America, Central America + Mexico + Antilles, and North America). While the informal group, called A. capillus-veneris, by Tryon & Tryon (1982) included A. raddianum and A. poiretii, Huiet & al. (2018) showed that capillus-veneris belong a different lineage and not closely related to these two species.
Based on the recent phylogenetic advances pointed out above and in order to start to revise the entire genus Adiantum, the present paper has as a main goal to present the taxonomic treatment of the neotropical species of the A. raddianum group.
Material and methods
The present taxonomic treatment was based on the phylogenetic data by Hirai & al. (2016) that showed the monophyletism of the Adiantum raddianum group and that it has A. poiretii group as sister.
Morphological data were taken from herbarium specimens borrowed from 39 herbaria worldwide (see Acknowledgements) and recent collections by the authors, whose specimens were deposited at the SP Herbarium.
Some species extend their distribution beyond the neotropical region in the north and south. In these cases, the entire distribution for each species was cited.
Selected or examined specimens appear in Appendix 1 ( supplemental content online (wi.49.49302_supplement.pdf)). For the selected specimens only one specimen was cited per state, province, or department (in alphabetic order) for each country (from north to south, from east to west). For those species with only a few specimens studied, all specimens were cited. When the specimens were used to prepare the images of the spores by SEM (Fig. 1) or to draw the plates (Fig. 2–9) they were also cited among the selected or examined specimens. The list of all studied exsiccatae is presented in the Appendix 2 ( supplemental content online (wi.49.49302_supplement.pdf)).
All elevation data recorded in feet were converted to metres and appear in brackets as such in the specimen citations.
Taxonomic treatment
Sixteen species were recognized into the Adiantum raddianum group in the neotropical region. This group of species can be recognized by pseudopedate (in A. patens s.l.) to 1–5-pinnate laminae, veins ending in sinuses at the sterile segment margins, and round-reniform sori.
Additionally, the species that belong to this group have rhizome erect to short-creeping, rhizome scales varying from entire to slightly ciliate, pinnules cuneate to flabellate or orbicular or dimidiate, the colour of the stalk stopping abruptly at the base of the pinnules (articulate) or not. The spores in this group have rugate to rugulate surface and do not vary much among the species (Fig. 1A–I). According to Tryon & Lugardon (1991), the spores in Adiantum are morphologically uniform.
Based on the morphological characters pointed out above, we included in these taxonomic treatment three species that were not sampled in the phylogenetic study by Hirai & al. (2016): Adiantum imbricatum, A. lobatum and A. subvolubile.
Key to the species of Adiantum raddianum group in the neotropics
1. Lamina pseudopedately divided 10. A. patens s.l. (Fig. 6H–Q)
– Lamina pinnately divided 2
2. Lamina at base 1-pinnate or (rarely 2-pinnate or 3-pinnate, when 2-pinnate rachis trifurcate) 3
– Lamina at base 2–5-pinnate or subdichotomously divided 5
3. Rhizome long-creeping; rhizome scales with entire margins; from Peru and Bolivia 13. A. ruizianum (Fig. 8A–F)
– Rhizome short-creeping; rhizome scales with ciliate margins; endemic from Mexico 4
4. Lamina with 5–10 pairs of lateral pinnae; ultimate segments suborbicular, slightly overlapping main rachis 3. A. galeottianum (Fig. 3A–F)
– Lamina with 27–55 pairs of lateral pinnae; ultimate segments dimidiate, strongly overlapping main rachis 14. A. shepherdii (Fig. 8G–M)
5. Lamina subdichotomously divided at base 11. A. pseudotinctum (Fig. 7A–F)
– Lamina (2 or)3–5-pinnate at base 6
6. Abaxial lamina surface glandular, glands spread over surface at segments 8. A. moorei (Fig. 5G–L)
– Abaxial lamina surface eglandular or if glandular, glands restricted to segment base 7
7. Ultimate segments articulate or subarticulate, articulation at apex of stalk swollen, dark colour of stalk stopping abruptly at point of articulation and not passing into base of segments 8
– Ultimate segments not articulate, apex of stalk not swollen, dark colour of stalk gradually passing into base of segments 9
8. Ultimate segments articulate; lamina glabrous on both surfaces 9. A. orbignyanum (Fig. 6A–G)
– Ultimate segments subarticulate; lamina abaxially with hairs along and between veins, hairs (0.3–)0.4–0.6 mm long, acicular, (3–)5- or 6-celled, hyaline, spreading, adaxially with similar hairs mostly near segment base 5. A. imbricatum (Fig. 4A–E)
9. Stipe and stalks pubescent 10
– Stipe and stalks completely glabrous or rarely with linear scales 11
10. Ultimate segments abaxially mostly with hairs, hairs acicular along and between veins, 0.3–0.7 mm long, (3–)5- or 6-celled, glandular hairs 0.05–0.1 mm long, mostly near segment base; sori not yellow-farinose 4. A. henslovianum (Fig. 3G–L)
– Ultimate segments abaxially only with glandular hairs along veins mostly near segment base, 0.05–1 mm long, 2-celled; sori yellow-farinose 6. A. lobatum (Fig. 4F–K)
11. Rhizome long-creeping 12
– Rhizome short-creeping, nodose or suberect 13
12. Stalk of proximal pinna pair 0.5–1(–3) mm long; indusia yellow-farinose or with glands between sporangia 15. A. subvolubile (Fig. 9A–F)
– Stalk of proximal pinna pair (3–)7–20 mm long; indusia not yellow-farinose 16. A. tinctum (Fig. 9G–L)
13. Proximal acroscopic pinnule of each pinna overlapping in all main rachis . 2. A. concinnum (Fig. 2G–M)
– Proximal acroscopic pinnule of each pinna not overlapping main rachis or, if overlapping only distally 14
14. Indusia not yellow-farinose, lacking glands between sporangia . 12. A. raddianum (Fig. 7G–O)
– Indusia yellow-farinose or with glands between sporangia 15
15. Pinnule of proximal pinnae pair not overlapping main rachis (South America) 7. A. lorentzii (Fig. 5A–F)
– Pinnule of proximal pinnae pair often overlapping main rachis distally (Mexico) . 1. A. alan-smithii (Fig. 2A–F)
Fig. 1.
Spores of Adiantum raddianum group. – A. concinnum – A: distal view; B: proximal view. – A. lorentzii – C: distal view; D: proximal view. – A. orbignyanum – E: distal view; F: Proximal view. – A. pseudotinctum – G: proximal view. – A. raddianum – H: distal view. –A. tinctum – I: proximal view. – A, B from Delascio & Lópes 12984 (VEN); C, D from Martínez & Prado 1877 (SP); E, F from Fortunato & al. 8186 p.p. (INTA); G from Hirai & Prado 691 (SP); H from Prado & al. 2037 (SP); I from Kessler & al. 9471 (LPB). – Scale bars: A–I = 10 µm.
1. Adiantum alan-smithii R. Y. Hirai & al. in Syst. Bot. 39: 382. 2014. – Holotype: Mexico, Chiapas, Ocozocoautla de Espinosa, Río de la Venta at the Chorreadero near Derna, 800–1000 m, 24 Aug 1972, D. E. Breedlove 27375 (MO barcode MO2293616!; isotypes: DS660339 [image!], DUKE248073 [photo!], MEXU barcode MEXU00220786 [photo!]). – Fig. 2A–F.
Morphological description — Plants terrestrial. Rhizomes c. 5 mm in diam., moderately slender, short-creeping to suberect, compact, dark brown, scaly, scales 1.4 × 0.2 mm, lanceolate, castaneous, concolorous, shiny, basifixed, margins entire, apex acuminate. Fronds closely spaced (1–3 mm apart), arching; stipes 5–7.5 cm × 0.5–1 mm, ¼–⅓ frond length, castaneous to dark brown, lustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis slightly flexuous, castaneous to dark brown, glabrous; laminae herbaceous, 12.5–16 × 6.2–10.2 cm, lanceolate to ovate-lanceolate, 2- or 3-pinnate proximally, 1- or 2-pinnate distally; pinnae 5–8 pairs, stalked, stalk of proximal pinna pair 2.5–4 mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna often overlapping main rachis distally; ultimate segments 0.9–2.2 × 0.7–1.6 cm, stalked, stalk 2.5–3.5(–4) mm long, non-articulate, with dark colour passing into pinnule base, obovate to flabellate, cuneate to truncate at base, apex round, sometimes deeply incised, sterile margins lobed to slightly denticulate, abaxially and adaxially glabrous; veins free, forking, ending in sinuses between marginal teeth; sori (2–)4–10 per pinnule, confined to distal margins of segments; indusia 1–2 mm wide, orbicular to reniform with deep sinuses, yellow-farinose, farina deposited on abaxial surface among sporangia.
Distribution and ecology — Adiantum alan-smithii is restricted to the central depression of Chiapas, Mexico, where it occurs on cliff faces and bluffs in tropical deciduous and seasonal evergreen forest; 800–1350 m elevation.
Remarks — Adiantum alan-smithii is easily recognized, when fertile, by its yellow-farinose indusia (Fig. 2F). It is also distinct by having laminae with 5–8 pairs of pinnae, the proximal acroscopic pinnule of each pinna often overlapping the main rachis distally, the segments stalked and mostly broadly flabellate, the rachis ± flexuous toward the tip (Fig. 2A), and the stalk non-articulate with its dark colour passing into the segment base (Fig. 2D). By comparison, A. raddianum has non-farinose indusia and proximal acroscopic pinnules that do not overlap the main rachis.
2. Adiantum concinnum Humb. & Bonpl. ex Willd., Sp. Pl. 5: 451. 1810. – Lectotype (designated by Tryon 1964: 168): [Venezuela, Dist. Federal, Caracas], “Cumana”, F. W. H. A. von Humboldt & A. J. A. Bonpland s.n. (B barcode B-W20099-020 [image!]; isolectotypes: B barcode B 20 0003565!, NY barcode NY00144535 [fragment ex B]!). – Fig. 1A, B, 2G–M.
= Adiantum concinnum var. subscandens Hook. & Baker, Syn. Fil.: 123. 1867. – Lectotype (designated here): Ecuador, Chimborazo, Mt. Chimborazo, R. Spruce 5706 (K barcode K000656192!; isolectotype: P barcode P01285920!).
– Adiantum concinnum var. laxum T. Moore, Index Fil.: 23. 1857, nom. nud.
Morphological description — Plants terrestrial. Rhizomes c. 5 mm in diam., moderately slender, short-creeping to suberect, compact, castaneous, scaly, scales 3–5 × 0.2–1 mm, lanceolate, sometimes linear, castaneous to dark brown, concolorous, shiny, basifixed, margins entire, apex acuminate. Fronds closely spaced (0.2–0.5 cm apart), arching to pendent; stipes 4–22 cm × 1–3 mm, ¼–⅓ frond length, castaneous to atropurpureous, lustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis not flexuous, castaneous to atropurpureous, glabrous; laminae herbaceous, 16–75 × 4–30 cm, lanceolate to ovate-lanceolate, 2- or 3-pinnate proximally, 2- or 3-pinnate distally; pinnae 9–17 pairs, stalked, stalk of proximal pinna pair 1–1.5(–2.5) mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna overlapping in all main rachis, subsessile, mostly divided into 2 (or 3) ultimate segments; ultimate segments 0.4–2 × 0.5–2.2 cm, stalked, stalk 0.1–0.5 mm long, non-articulate, with dark colour passing into pinnule base or slightly so, obovate to flabellate, cuneate at base, sometimes truncate, apex round, sterile margins entire, lobed, incised or sometimes denticulate distally, abaxially and adaxially glabrous; veins free, forking, ending at entire thickened pinnule margins or shallow sinuses; sori 4–17 per pinnule, confined to distal margins of segments; indusia 0.5–2 mm wide, reniform to round-reniform, with often deep sinuses, glabrous.
Fig. 2.
Adiantum alan-smithii – A: habit; B: rhizome scale; C: sterile pinnule; D: detail of segment base; E: fertile pinnule, abaxial view with indusia; F: detail of indusium detached abaxially with sporangia and yellow-farina. – A. concinnum – G: habit; H: rhizome scale; I: furcate stalk of proximal pinnules; J: sterile pinnule; K: detail of segment base; L: fertile pinnule, abaxial view with indusia; M: detail of indusium adaxially. – A–E from Breedlove & Smith 27375 (MO); F from Lópes 941 (MO); G–M from Maya 2200 (NY) – Drawn by Klei Sousa.
Distribution and ecology — It occurs on moist banks and in partial shaded forests of Mexico, Guatemala, Belize, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Greater and Lesser Antilles, Colombia, Venezuela, Trinidad, Ecuador and Peru; 50–2300 m elevation.
Remarks — Adiantum concinnum is characterized by the proximal acroscopic pinnule of each pinna often overlapping the main rachis (Fig. 2G), subsessile, mostly divided into 2 ultimate segments (Fig. 2I). The first pinnule overlaps the rachis because it has a very small stalk (1–1.5(–2.5) mm long). The most similar species is A. subvolubile, which differs in having yellow-farinose indusia, the farina deposited on the abaxial surface among the sporangia.
Adiantum concinnum was cited by Prado (2010) as occurring in Brazil based on specimens collected in 1963, by Pires & al. 9698 (K, LP) and Pires & al. 9698A (UB). These specimens were reported from a locality between Brasília and Niquelândia, in C Brazil, an area out of the main known distribution of this species. Both materials are fragments of fronds and without rhizomes. They are very similar to A. concinnum in having the proximal acroscopic pinnule of each pinna often overlapping the main rachis. However, recently the present authors made a field trip to the region cited on the labels of these specimens and this species was not found. At the moment, A. raddianum is the unique species of the group that occurs in this area. Thus, the occurrence of A. concinnum, as a native species in Brazil, was not confirmed here.
3. Adiantum galeottianum Hook., Sp. Fil. 2: 10, t. 80B. 1851. – Lectotype (designated by Smith 1981: 27): Mexico, Oaxaca, [Juquila del Sur], H. Galeotti 6561 (K barcode K000484001!; isolectotypes: BM s.n.!, BR barcodes BR0000006712853 [image!], BR0000006712198 [image!], BR0000006712525 [image!], GENT barcode GENT0000090032752 [image!], GH barcode GH00020365 [image!], P barcodes P00608572 [image!], P00608573 [image!]). – Fig. 3A–F.
Morphological description — Plants terrestrial. Rhizomes c. 5 mm in diam., moderately slender, short-creeping, compact, dark brown, scaly, scales 2–3 × 0.1–0.2 mm, linear-lanceolate, golden brown, concolorous, shiny, basifixed, margins short ciliate, cilia 0.05–0.1 mm long, tortuous, delicate, with same colour as body of scale, apex apiculate. Fronds closely spaced (1–2 mm apart), arching; stipes 8–20 cm × 1–1.5 mm, ⅓–½ frond length, dark brown, sublustrous, glabrous or sparsely pubescent, with a few scales at base similar in morphology to those of rhizomes, glandular hairs, c. 0.05 mm long, 2-celled, red-brown; rachis not flexuous, dark brown, glabrous or sparsely pubescent, indument similar stipes, sometimes glaucous and rarely with linear scales, scales c. 0.5 mm long, red-brown; laminae coriaceous, 12–19 × 4.5–12.8 cm, usually linear, sometimes deltate, 1-pinnate proximally, rarely 2-pin-nate, when 2-pinnate ± trifurcate, 1-pinnate distally; pinnae 5–10 pairs, stalked, stalk of proximal pinna pair 2–5 mm long, apex slightly reduced, subopposite or alternate; proximal acroscopic pinnule of each pinna slightly overlapping main rachis at base; ultimate segments 0.8–3.3 × 0.8–2.6 cm, subsessile or short-stalked, stalk 0.1–2 mm long, non-articulate, with dark colour slightly passing into pinnule base, suborbicular, subcordate, sometimes flabellate, round at base, sometimes truncate, apex round, sterile margins irregularly crenate or subentire, abaxially and adaxially glabrous; veins free, forking, ending at whitish cartilaginous pinna margins, sometimes castaneous; sori 5–20 per pinna, all on acroscopic margin; indusia 1.5–2 mm wide, orbicular to reniform, with deep sinuses, glabrous.
Distribution and ecology — It grows on wet banks along roadside in pine woods, pine-oak woods, also on moist banks of streams in Mexico (endemic); 600–900 m elevation.
Remarks — Adiantum galeottianum can be recognized by coriaceous laminae, mostly 1-pinnate proximally, and suborbicular ultimate segments (Fig. 3A, C, E). Adiantum shepherdii is the other species endemic to Mexico with similar division pattern of the laminae, but differs by having obliquely flabellate or dimidiate ultimate segments.
4. Adiantum henslovianum Hook. f. in Trans. Linn. Soc. London 20: 169. 1847. – Lectotype (designated by Tryon 1964: 164): Ecuador, Galapagos, Hab. James and Charles Islands, Sep 1835, C. Darwin s.n. (K barcode K000633115!; isolectotypes: CGE barcodes CGE00187 [image!], CGE00188 [image!]). – Fig. 3G–L.
Fig. 3.
Adiantum galeottianum – A: habit; B: rhizome scale; C: sterile pinnule; D: detail of segment base; E: fertile pinnule, abaxial view with indusia; F: detail of indusium adaxially plus sporangia. – A. henslovianum – G: habit; H: rhizome scale; I: sterile pinnule; J: detail of segment base; K: fertile pinnule, abaxial view with indusia; L: detail of indusium adaxially with hairs. – A–F from Mickel & Hellwig 3992 (NY); G–J from Werff 1400 (NY); K, L from Øllgaard & al. 90675 (QCA) – Drawn by Klei Sousa.
= Adiantum sessilifolium Hook., Sp. Fil. 2: 44, t. 85B. 1851. – Lectotype (designated by Tryon 1964: 164): Peru, Chachapoyas, A. Mathews 1855 (K barcode K000633114!; isolectotype: US barcode US00142201 [fragment]!).
= Adiantum laetum Mett. ex Kuhn in Linnaea 36: 76. 1869. – Lectotype (K designated by Tryon 1964: 164, as first step; second step designated here): Peru, Chachapoyas, A. Mathews 3295 (K barcode K000633111!; isolectotypes: BM barcode BM001067928!, K barcode K000633112!).
= Adiantum henslovianum var. macrosorum Hieron. in Hedwigia 48: 238. 1909. – Lectotype (designated here): Peru, near Leimabamba, A. Stübel 1031 (B barcode B 20 0004574!).
Morphological description — Plants terrestrial. Rhizomes 7–10 mm in diam., slightly stout, short-creeping, compact, castaneous, scaly, scales 2.2–2.5 × 0.2–0.8 mm, lanceolate, castaneous, concolorous, sublustrous, basifixed, margins entire, apex acuminate. Fronds closely spaced (1–3 mm apart), arching; stipes 11–36.5 cm × 0.5–1 mm, ¼–⅔ frond length, castaneous to reddish, sublustrous, densely to sparsely pubescent, hairs glandular or acicular, rarely glabrous, glandular hairs c. 0.05–0.15 mm long, 2-celled, sometimes furcate at apex, hyaline to red-brown, acicular hairs, 0.2–0.3 mm long, 3–5-celled, hyaline to red-brown, with sparsely filiform scales, scales 0.7–2.1 mm, reddish and few scales at base of stipe similar in morphology to those of rhizomes; rachis not flexuous, castaneous to reddish, pubescent like petioles or rarely glabrous, with sparsely filiform scales, like those of petioles; laminae herbaceous, rarely chartaceous, 13.7–45(–62.5) × 4.5–25 cm, ovate-triangular to ovate-lanceolate, 1–3-pinnate proximally, 1- or 2-pinnate distally; pinnae 12–24(–26) pairs, stalked, stalk of proximal pinna pair 1–1.5(–2) mm long, rarely c. 5 mm long, apex gradually reduced, alternate to subopposite; proximal acroscopic pinnule of each pinna often overlapping in all main rachis; ultimate segments 0.8–2.1 × (0.3–)0.7–1.6 cm, subsessile, rarely stalked, stalk c. 0.05(–1.5) mm long, non-articulate, with dark colour passing into pinnule base, dimidiate or shortly dimidiate to obovate, sometimes flabellate, cuneate at base, sometimes truncate, apex round, sterile margins entire basiscopically, acroscopic margins lobed and denticulate, rarely incised, abaxially and adaxially with hairs or rarely glabrous, hairs along and between veins, acicular hairs, 0.3–0.7 mm long, (3–)5- or 6-celled, hyaline, spreading, glandular hairs like those rachises extending near segment base, rarely glabrous adaxially; veins free, forking, ending in minute sinuses between denticulate margins; sori 1–9 per pinnule, confined to acroscopic or distal margins; indusia 1–3 mm wide, orbicular to reniform, widely reniform (rarely suboblong), with deep sinuses and mostly with acicular hairs on surface, hyaline or reddish.
Distribution and ecology — This species grows on rocky slopes in Venezuela, Ecuador and Peru; 1400–2700 m elevation.
Remarks — Adiantum henslovianum has proximal the acroscopic pinnule of each pinna often overlapping the main rachis (Fig. 3G) and entire rhizome scales (Fig. 3H).
This species is quite variable morphologically. The specimens from Peru have only acicular hairs on the stipes and rachis, whereas the plants from Ecuador have mostly glandular hairs on the stipes and rachis. On the other hand, Mathews 3295 (K) is a glabrous specimen. No other morphological differences distinguish these specimens.
5. Adiantum imbricatum R. M. Tryon in Amer. Fern J. 47: 142, t. 15. 1957. – Holotype: Peru, Cuzco, La Tranca, Valle de Río de Huarancalqui o Mapillo, 6000 ft [1828 m], Jun 1923, C. Bües 1377 (US barcode US00142186!; isotypes: GH barcode GH00020369 [image!], USM barcode USM000838 [image!]). – Fig. 4A–E.
Morphological description — Plants terrestrial. Rhizomes and rhizome scales not seen. Fronds apparently erect; stipes c. 15 cm × 1 mm, c. ½ frond length, dark brown, sublustrous, with a few scales at base and sparsely pubescent along stipes, scales 1–1.5 × 0.1–0.5 mm, lanceolate, castaneous, concolorous, shiny, basifixed, apex acute, margins entire, hairs (0.1–)0.2–0.3 mm long, (2 or)3- or 4-celled, hyaline to red-brown; rachis not flexuous, dark brown, densely pubescent, hairs similar to those of stipes; laminae chartaceous, 8.5–18.3 × 2.2–5.5(–7.6) cm, linear-lanceolate, 2-pinnate proximally, 1-pinnate distally; pinnae 9–15 pairs, stalked, stalk of proximal pinna pair 3–6 mm long, apex not reduced, alternate; proximal acroscopic pinnule of each pinna often overlapping main rachis; ultimate segments 0.8–2.3 × 0.6–1.6 cm, stalked, stalk 1–1.5 mm long, densely pubescent, hairs similar to those of rachis, subarticulate, with dark colour not passing into pinnule base, flabellate, slightly cuneate to truncate at base, apex round, sterile margins denticulate, abaxially with hairs along and between veins, hairs (0.3–)0.4–0.6 mm long, acicular, (3–)5- or 6-celled, hyaline, spreading, adaxially with similar indument, but hairs mostly near segment base; veins free, forking, ending in sinuses of sterile segments between teeth; sori 8–15 per pinnule, confined to distal margins; indusia 1.5–2 mm wide, orbicular to reniform, with deep sinuses, glabrous.
Distribution and ecology — It is found in rocky places only in Peru; 1500–1850 m elevation.
Remarks — Adiantum imbricatum is recognized by the subarticulate segments (Fig. 4C), densely pubescent (Fig. 4C–E), the hairs (0.1–)0.2–0.3 mm long, (2 or)3- or 4-celled, hyaline to red-brown. Tryon & Stolze (1989) called attention for the presence of these hairs, as well as the dark colour of the stalk stopping abruptly at the base of the segments.
Fig. 4.
Adiantum imbricatum – A: fertile frond; B: sterile pinnule; C: detail of segment base with hairs; D: fertile pinnule, abaxial view with indusia; E: detail of indusium adaxially. – A. lobatum – F: habit; G: rhizome scale; H: sterile pinnule; I: detail of segment base with minute hairs; J: fertile pinnule, abaxial view with indusia; K: detail of indusium detached abaxially with sporangia and yellow-farina. – A–E from Bües 1305 (UC); F–K from Correll & Smith P801 (US) – Drawn by Klei Sousa.
6. Adiantum lobatum C. Presl, Reliq. Haenk. 1(1): 62, t. 10, fig. 4. 1825, ex descriptione et icone. – Type: Ecuador, [Guayas], Guayaquil, 1790, T. P. X. Haenke s.n. (PR n.v.). – Fig. 4F–K.
Morphological description — Plants terrestrial. Rhizomes c. 2 mm in diam., slender, short-creeping, ± compact, castaneous, scaly, scales 1.5–2 × 0.2–0.4 mm, lanceolate, castaneous to blackish, concolorous, shiny, basifixed, margins short ciliate to entire, cilia c. 0.05 mm long, straight, with same colour as body of scale, apex acuminate. Fronds closely spaced (c. 4 mm apart), arching; stipes 11–22 cm × 0.5–1.5 mm, ½–⅔ frond length, dark brown, sublustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis not flexuous, dark brown, adaxially pubescent, glandular hairs 0.05–0.1 mm long, 2-celled, hyaline; laminae herbaceous, 10.5–13 × 10–13.5 cm, deltoid to ovate-lanceolate, 2- or 3-pinnate proximally, 1- or 2-pinnate distally; pinnae 4–11 pairs, stalked, stalk of proximal pinna pair 15–26 mm long, apex slightly reduced, alternate; proximal acroscopic pinnule of each pinna not overlapping main rachis; ultimate segments 0.8–2.7 × 0.8–2.6 cm, stalked, stalks (0.05–)0.15–0.4 mm long, non-articulate, with dark colour passing into pinnule base, flabellate to dimidiate, cuneate at base, apex round, sterile margins entire lobed and crenulate, sometimes incised distally or on acroscopic margin, abaxially and adaxially with glandular hairs along veins concentrated near segment base, glandular hairs 0.05–1 mm long, 2-celled, hyaline; veins free, forking, ending at sinuses; sori 6–20 per pinnule, confined to distal or on acroscopic margins; indusia 1–2 mm wide, orbicular to reniform, with deep sinuses, yellow-farinose.
Distribution and ecology — It grows on rocky hillsides of Ecuador and Peru; 150–1400 m elevation. This species occurs on the W side of the Andes, which is a drier place.
Remarks — Adiantum lobatum is characterized by having laminae 2- or 3-pinnate proximally and 1- or 2-pin-nate distally (Fig. 4F), ultimate segments abaxially and adaxially with hairs along the veins only near the segment base (Fig. 4I), the hairs 0.05–1 mm long, 2-celled, hyaline, and yellow-farinose indusia (Fig. 4K).
As commented by Tryon & Stolze (1989), Adiantum lobatum is a rare species and is only known by few and old collections from Peru in 1960.
Adiantum lobatum is similar to A. patens s.l. and A. henslovianum by all having glandular hairs on the rachises. However A. lobatum can be easily distinguished from both by the yellow-farinose indusia (vs not yellow-farinose).
Mickel & Smith (2004) synonymized Adiantum lobatum in A. patens, but this latter species differs in having pseudopedate laminae (vs 2- or 3-pinnate in A. lobatum) and not yellow-farinose indusia.
7. Adiantum lorentzii Hieron. in Bot. Jahrb. Syst. 22: 393. 1896. – Lectotype (designated here): Argentina, Tucumán, Siambón, 8 May 1872, P. G. Lorentz 163 (US barcode US00142188!; isolectotypes: B barcodes B 20 0003409 p.p.!, B 20 0005154!, B 20 0005159!, CORD4601 [image!], F barcode F0075878F [image!]). – Fig. 1C, D, 5A–F.
= Adiantum cuneatum var. veneris Griseb. in Abh. Königl. Ges. Wiss. Göttingen 19: 275. 1874. – Lectotype (designated by Giudice 1999: 290): Argentina, Tucumán, Siambón, P. G. Lorentz 163 (CORD4601 [image!]).
Morphological description — Plants terrestrial. Rhizomes c. 5 mm in diam., moderately slender, short-creeping to suberect, compact, castaneous, scaly, scales 1.8–3.2 × 0.3–0.5 mm, lanceolate, castaneous, concolorous, shiny, basifixed, margins entire, apex acuminate. Fronds closely spaced (up to 5 mm apart), arching to pendent; stipes 6–25 cm × 0.8–1.5 mm, ⅓–½ frond length, dark brown, castaneous to atropurpureous, lustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis not flexuous or slightly flexuous, dark brown, castaneous to atropurpureous, glabrous, rarely with linear scales (mainly in forks or axes); laminae herbaceous, 17–39 × 10.5–30 cm, ovate-lanceolate, 3- or 4-pinnate proximally, 2- or 3-pin-nate distally; pinnae 6–11 pairs, stalked, stalk of proximal pinna pair 11–41 mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna not overlapping main rachis; ultimate segments 0.8–2.8 × 0.8–3 cm, stalked, stalk 2–5 mm long, non-articulate, with dark colour slightly passing into pinnule base, obovate to flabellate, cuneate, sometimes truncate at base, apex round, sterile margins entire to denticulate, lobed or incised distally, abaxially and adaxially glabrous; veins free, forking, ending at sinuses; sori 2–12 per pinnule, confined to distal margins; indusia 1–2 mm wide, orbicular to reniform, with often deep sinuses, yellow-farinose or with glands.
Distribution and ecology — It occurs in semideciduous and wet montane forests of Peru, Bolivia, Brazil and Argentina; (430–)700–2500 m elevation.
Remarks — Adiantum lorentzii can be distinguished from A. raddianum by having yellow-farinose indusia (Fig. 5F), the farina is produced by the glandular hairs. Sometimes this farina is not present because it may be related to the stage of the plant, but a very careful look it is possible to see the glandular hairs below the indusia and among the sporangia. These glands are very small (≤0.05 mm long, 2-celled) and difficult to be observed. The presence of sporangia itself and fungi may obscure these glandular hairs.
Fig. 5.
Adiantum lorentzii – A: habit; B: rhizome scale; C: sterile pinnule; D: detail of segment base; E: fertile pinnule, abaxial view with indusia; F: detail of indusium detached abaxially with sporangia and yellow-farina. – A. moorei – G: habit; H: rhizome scale; I: sterile pinnule; J: detail of segment base with glands; K: fertile pinnule with glands, abaxial view with indusia; L: detail of indusium adaxially with glands. – A–F from Martínez & Prado 1878 (SP); G–L from Seidel 1429 (SP) – Drawn by Klei Sousa.
For a long time, these two species have been misinterpreted in Bolivia, Brazil and Argentina. In general, these species have been separated by form and size of the ultimate segments or pinnules (almost entire in Adiantum raddianum and deeply incised in A. lorentzii; e.g. Giudice 1999; Winter & al. 2011), however we observed that these features are quite variable and cannot be used to distinguish them. Adiantum lorentzii has been cited for Brazil (e.g. Prado & al. 2010), but this species is known in Brazil based on few specimens that might be a distinct species, but more studies are necessaries to confirm this hypothesis.
Adiantum alan-smithii resembles A. lorentzii (e.g. Calatayud & al. 3045 (NY, UC), Solomon & Urcullo 14157 (MO)) by having yellow-farinose indusia, but differs by flexuous rachises and mainly by pinnules overlapping the main rachis; it is also restricted to Mexico (Chiapas).
8. Adiantum moorei Baker in Gard. Chron. 1873: 811. 1873 ≡ Adiantum amabile T. Moore in Gard. Chron. 1868: 1090. 1868, nom. illeg. [non Adiantum amabile Liebm.in Kongel. Danske Vidensk. Selsk. Skr., Naturvidensk. Math. Afd., ser. 5, 1: 265. 1849]. – Lectotype (designated by Tryon 1964: 169): Cultivated by Veitch, originally from Peru, R. Pearce s.n. (K barcode K000633103!). – Fig. 5G–L.
= Adiantum rufopunctatum Mett. ex Kuhn in Bot. Jahrb. Syst. 1: 350. 1881. – Lectotype (designated by Tryon 1964: 169): Bolivia, Yungas, s.d., A. C. V. D. d'Órbigny 165 (B barcode B 20 0007084!; isolectotypes: BR barcode BR0000006716455 [image!], P barcode P00608520 [image!], NY barcode NY00144570 [fragment]!).
= Adiantum boliviense Christ & Rosenst. in Repert. Spec. Nov. Regni Veg. 5: 230. 1908. – Lectotype (designated by Tryon 1964: 169): Bolivia, La Paz, Sud Yungas, Yanacachi prope La Florida, 16°S, 1600 m, 21 Nov 1906, O. Buchtien 459 (S05-9808!; isolectotypes: P barcode P00608521 [image!], UC barcode UC478394!, US barcode US00142178!).
= Adiantum decorum var. quadripinnatum Rosenst. in Meded. Rijks-Herb. 19: 8. 1913, as “quadripinnata”. – Lectotype (designated by Sundue & al. 2010: 202): Bolivia, Cochabamba or Santa Cruz, Yungas de San Mateo, 1500 m, s.d., T. C. J. Herzog 1995 (US barcode US00142180!).
Morphologicaldescription—Plantsterrestrial.Rhizomes c. 4 mm in diam., moderately slender, short-creeping, compact, castaneous, scaly, scales 3–5 × 0.3–0.5 mm, lanceolate, castaneous, concolorous, shiny, basifixed, margins entire, or rarely short ciliate, cilia c. 0.05 mm long, with same colour as body of scale, rarely with short-projections on scale surface, c. 0.05 mm long, apex filiform. Fronds closely spaced (1–2 mm apart), arching; stipes 9–16.5 cm × 0.5–1 mm, ⅔–½ frond length, castaneous to dark brown, sometimes glaucous, lustrous, glabrous, with a few scales at base like those of rhizomes; rachis not flexuous, castaneous to dark brown, sometimes glaucous, glabrous; laminae herbaceous, 19–40 × 8–27 cm, ovate to deltate, 3- or 4-pinnate proximally, 1–3-pinnate distally; pinnae 5–12(–16) pairs, stalked, stalk of proximal pinna pair 3.5–25 mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna not overlapping main rachis; ultimate segments 0.6–1.2(–2.5) × 0.7–1.6(–2) cm, stalked, stalk 1–1.5(–2) mm long, non-articulate, with dark colour passing into pinnule base, obovate, sometimes slightly dimidiate, cuneate at base, apex round, sterile margins incised and denticulate distally, sometimes deeply incised, abaxially with glandular hairs between veins, c. 0.05 mm long, 2-celled, yellowish to orangish, sometimes hyaline or sometimes with shiny yellowish dots (farinose), spreading, adaxially glabrous or with sparsely glandular hairs like those from abaxial surface; veins free, forking, ending in sinuses of sterile segments; sori (1–)4–9 per pinnule, confined to distal margins; indusia 1–1.5 mm wide, orbicular, orbicular to reniform, with deep sinuses, with orangish glandular hairs or rarely yellow-farinose.
Distribution and ecology — It is found in montane wet forests and semideciduous forests, on steep slopes of Peru, Bolivia and Argentina; (670–)1100–1500(–1820) m elevation.
Remarks — This species is easily recognized by the laminae with glandular hairs between the veins (Fig. 5J–L), these hairs have c. 0.05 mm long, 2-celled, they are yellowish to orangish, sometimes hyaline or sometimes the laminae with shiny yellowish dots (farinose).
Villarroel & al. 517 (NY) differs a little bit by having short ciliate rhizome scales; and the specimens Bartlett 20374 (NY) and Wislizems 1139 (MO) have few glands on the laminae distally, but in other features, they match with Adiantum moorei.
The binomial Adiantum moorei was previously synonymized in A. raddianum (e.g. Tryon & Stolze 1989; Lellinger 1989) and adopted by Sundue & al. (2010) and Sundue (2011), but A. moorei is the oldest name to be applied to this taxon.
9. Adiantum orbignyanum Kuhn in Linnaea 36: 78. 1869. – Lectotype (designated by Tryon 1964: 175): Bolivia, 1863, G. Mandon 52 (B barcode B 20 0005841!; isolectotype: NY barcode NY00144561 [fragment] p.p.!). – Fig. 1E, F, 6A–G.
= Adiantum tenerum var. rhomboideum Kunth ex Griseb., Pl. Lorentz.: 275. 1874, ex descriptione. – Type: [Argentina], Catamarca, Vayas Altas, 9–11 000 ft [2743–3352 m], P. G. Lorentz s.n. (GOET? n.v.).
Morphological description — Plants terrestrial. Rhizomes 1.5–2.5 mm in diam., slender, long-creeping, sometimes ± compact and nodose, castaneous to dark brown, scaly, scales 1–1.5 × 0.2–0.4 mm, lanceolate, castaneous, concolorous, shiny, basifixed, margins entire to short ciliate distally, cilia c. 0.1 mm long, tortuous, with same colour as body of scale, apex acute. Fronds spaced ((1–)8–10 mm apart), arching; stipes 5–18 cm × 0.5–1 mm, ⅙–¼ frond length, dark brown, sublustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis ± flexuous, dark brown, glabrous; laminae chartaceous, 18.5–33.5 × 4.2–12.2 cm, oblong-lanceolate to lanceolate, 2- or 3-pinnate proximally, 1- or 2-pinnate distally, apex gradually reduced; pinnae 5–14 pairs, stalked, stalk of proximal pinna pair 1–3 mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna overlapping main rachis; ultimate segments 0.7–1.9 × 0.5–1.6 cm, stalked, stalk 1–2 mm long, articulate, distal portion of stalk swollen, sometimes with few glandular hairs at base of swollen, hairs c. 0.1 mm long, 2-celled, hyaline or red-brown, dark colour stopping abruptly at pinnule base, obovate to flabellate, cuneate at base, apex round, sterile margins entire to lobed and denticulate, abaxially and adaxially glabrous; veins free, forking, ending in sinuses of sterile segments; sori 4–10 per pinnule, confined to distal margins; indusia 1.5–2.5 mm wide, orbicular to reniform, with often deep sinuses, yellow-farinose or with hyaline glands.
Fig. 6.
Adiantum orbignyanum – A: habit; B: rhizome long-creeping; C: rhizome scale; D: sterile pinnule; E: detail of articulate segment base; F: fertile pinnule, abaxial view with indusia; G: detail of indusium detached abaxially with sporangia and yellow-farina. – A. patens s.l. – H: habit; I: rhizome scale; J, K: sterile pinnules; L, M: detail of segment bases glabrous and with hairs, respectively; N: fertile pinnule, abaxial view with indusia; O: detail of indusium adaxially; P: fertile pinnule with hairs, abaxial view with indusia; Q: detail of indusium adaxially with hairs. – A, C–G from Williams 2620 (NY); B from Barker 343 (MO); H–J, L, N, O from Tschudi 52 (VEN); K, M, P, Q from Mickel & Hellwig 3957 (NY) – Drawn by Klei Sousa.
Distribution and ecology — It occurs in evergreen forests, on stone walls along roadsides and in semideciduous forests of Ecuador, Peru, Bolivia and Argentina; 2100–4000 m elevation.
Remarks — Adiantum orbignyanum is easily recognized as being the unique species of the A. raddianum group in the neotropics with articulate segments and the distal portion of the stalks swollen (Fig. 6E), sometimes with few glandular hairs at the base of the swollen. Furthermore, it has yellow-farinose indusia (Fig. 6G).
The general aspect of the frond of Adiantum orbignyanum resembles A. subvolubile and A. tinctum. All species have the proximal acroscopic pinnule of each pinna overlapping the main rachis. But the last two species can be distinguished by the non-articulate ultimate segments.
10. Adiantum patens Willd., Sp. Pl. 5: 439. 1810. – Lectotype (designated by Tryon 1964: 165): Venezuela, Dist. Federal, Caracas, F. Bredemeyer s.n. (B-W. barcode B-W. 20078-010 [image!]; isolectotype: NY barcode NY00144563 [fragment]!). – Fig. 6H–Q.
= Adiantum parvulum Hook f. in Trans. Linn. Soc. London 20: 168. 1847. – Holotype: Ecuador, Galapagos, Charles Island, C. Darwin s.n. (CGE barcode CGE00185 [image!]).
– Adiantum hippocrepis A. Braun ex Salomon, Nomencl. Gefasskrypt.: 19. 1883, nom. nud.
Morphological description — Plants terrestrial. Rhizomes c. 3–5(–7) mm in diam., slender, short-creeping, rarely long-creeping, sometimes ± compact, dark brown, scaly, scales 1.7–4 × 0.3–0.5 mm, ovate-lanceolate to lanceolate, light brown, concolorous, shiny, basifixed, margins short ciliate, cilia c. 0.1 mm long, tortuous, with same colour as body of scale, apex acuminate. Fronds spaced (7–20 mm apart, sometimes c. 3 mm), arching; stipes (6–)25.5–46 cm × 1–3 mm, ½–¾ frond length, castaneous to atropurpureous, lustrous, glabrous or moderately to densely pubescent and/or scaly, glandular hairs 0.1–0.2 mm long, 2-celled, hyaline to whitish, sometimes red-brown and branched, filiform scales, 0.7–1.3 mm long, red-brown, few scales at base similar in morphology to those of rhizomes; rachis not flexuous, castaneous to atropurpureous, glabrous or moderately to densely pubescent and/or scaly like petioles; laminae herbaceous to chartaceous, 10–24 × to 8.5–29 cm, ovate to deltoid-ovate, pseudopedate; pinnae 4–12 pairs, stalked, stalk of proximal pinna pair 13–29 mm long, apex slightly reduced; ultimate segments (0.3–)0.6–2.2 × 0.4–1.8 cm, subsessile, stalks 0.05–1 mm long, non-articulate, with dark colour passing into pinnule base, dimidiate, sometimes obovate, cuneate at base, apex round, sterile margins lobed to crenate on acroscopic, sometimes on distal margins, entire on basiscopic margins, abaxially glabrous or pubescent, hairs acicular 0.2–0.8 mm long, 3–7-celled, spreading on and between veins, hyaline to reddish, sometimes with branched and glandular hairs near base, hyaline to reddish, adaxially glabrous or pubescent, hairs mostly acicular like those from abaxial laminar surfaces; veins free, forking, ending at cartilaginous margins; sori to (2–)6–12 per pinnule along acroscopic and distal margins; indusia 0.15–0.25 mm wide, orbicular to reniform, with deep sinuses, with or without hairs on surface, glabrous.
Distribution and ecology — It grows in montane forests of Mexico, Guatemala, Honduras, El Salvador, Costa Rica, Colombia, Venezuela, Ecuador, Peru, Bolivia and Brazil. Outside the neotropical region: Africa; 200–1900(–2100) m elevation.
Remarks — The best way to distinguish Adiantum patens s.l. is by its pseudopedate laminae (Fig. 6H). The rachis and ultimate segments are extremely variable from glabrous (Fig. 6J, N) to densely pubescent (Fig. 6K, M, P). Plants from Venezuela, Colombia and Bolivia can be totally glabrous, but there are intermediate specimens, e.g. Preuss 1669 (B) from Venezuela that has glandular hairs adaxially on the rachis.
The type specimen of Adiantum parvulum, collected by Darwin s.n in Galapagos, is a juvenile plant and has no rhizome. Some authors have considered this species synonymous of A. henslovianum (e.g. Wiggins & Porter 1971). But, in fact this juvenile specimen is A. patens. Adiantum patens s.l. (e.g. Werff 1342, NY) and A. henslovianum occur in Galapagos and can be easily misidentified or confused, for example on the sheet Howell 9196 p.p. (B) that contains both species in the same preparation.
Although Adiantum henslovianum resembles A. patens s.l. it differs by proximal acroscopic pinnule of each pinna overlapping the rachises from the proximal to distal rachises, short-creeping rhizome and the apical lamina end with some pairs of subopposite pinna.
Adiantum oatesii from Africa was treated by Ballard (1940) and Schelpe (1967) as variety and subspecies of A. patens, respectively. Hirai & al. (2016) and Huiet & al. (2018) showed that A. oatesii and A. patens (from Costa Rica and Ecuador) are conspecific, but in the present revision only specimens of A. patens from the neotropical region were revised.
Hirai & al. (2016) suggested that the specimens named as Adiantum patens from Mexico could represent a different species from those plants from Central America and the Andes. However, our first study (loc. cit.) did not sample the whole group and, for this reason, more studies are necessary to show how many species form the A. patens complex, establishing for each one of them their distributions and circumscriptions. Since the publication of the phylogeny (Hirai & al. 2016), we were not able to get more samples of the group for additional molecular analyses, involving specimens from different populations and localities throughout the area of occurrence of the species (including material from Venezuela, the type locality) and, because this, we decided to treat the A. patens complex sensu lato in the present revision. The study of the A. patens complex should be the target of another project.
11. Adiantum pseudotinctum Hieron. in Bot. Jahrb. Syst. 22: 394. 1896. – Lectotype (designated by Giudice 1999: 292): Argentina, Río Alto Paraná, Puerto Tamaren, Arroyo Ñacanguazu, 12 Feb 1883, G. Niederlein s.n. (B barcode B 20 0006576!). – Fig. 1G, 7A–F.
Morphological description — Plants terrestrial. Rhizomes c. 2 mm in diam., slender, long-creeping, castaneous, scaly, scales 1.2–2 × 0.1–0.5 mm, lanceolate, castaneous, concolorous, shiny, basifixed, margins entire, apex apiculate. Fronds spaced (2–)10–35 mm apart), arching; stipes 20–55 cm × 2–2.5 mm, ½–⅗ frond length, castaneous to red to dark brown, sublustrous, glabrous, with a few scales at base like those of rhizomes; rachises ± flexuous, castaneous to red to dark brown, glabrous; laminae herbaceous, 14–36 × 18–32.5 cm, deltoid to ovate, rarely ovate-lanceolate, subdichotomous, 3- or 4-pinnate proximally, 1–3-pin-nate distally, apex gradually reduced; pinnae (6–)8–10 pairs, stalked, stalks of proximal pinna pair 24–65 mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna not overlapping main rachis, 1st pinna as long as length of lamina; ultimate segments 0.9–2.9 × 1–2.3 cm, stalked, stalk 2–10 mm long, non-articulate, with dark colour passing into pinnule base, obovate to flabellate, cuneate at base, apex round, sterile margins lobed and incised distally, abaxially and adaxially glabrous; veins free, forking, ending at sinuses; sori (2–)7–16 per pinnule, confined to distal margins; indusia 0.5–1 mm wide, orbicular to reniform, with deep sinuses, glabrous.
Distribution and ecology — It grows on the edges of moist primary and secondary forests and on wet banks along roadsides; also in Araucaria forests; Brazil, Argentina, Paraguay and Uruguay; 50–1000 m elevation.
Remarks — Adiantum pseudotinctum is easily recognized by long-creeping rhizomes (Fig. 7A), however, when this character is absent it can be confused with other species mainly A. raddianum, as already commented by Giudice (1999). Analysing specimens without rhizome we observed that other morphological characters that can be used to distinguish it are the subdichotomous laminae divided and the 1st pinna as long as the length of the lamina (Fig. 7A).
12. Adiantum raddianum C. Presl, Tent. Pterid.: 158. 1836 ≡ Adiantum cuneatum Willd., Sp. Pl. 5: 450. 1810, nom. illeg. [non Adiantum cuneatum G. Forst., Fl. Ins. Austr.: 84. 1786]. – Lectotype (designated by Tryon 1964: 169, as first step; second step designated here): Brazil, Santa Catarina, “Ins. St. Catharina”, G. H. von Langsdorff s.n. (LE barcode LE00000018 [image!]; isolectotypes: LE barcode LE00000017 [image!], B-W. barcode B-W. 20096-010 [image!], B barcode B 20 0003818!, BM s.n.!) – Fig. 1H, 7G–O.
= Adiantum rubellum T. Moore in Gard. Chron. 1868: 866. 1868. – Lectotype (designated by Tryon 1964: 169): Cultivated by Veitch, originally from Bolivia (K barcode K000227555 [image!]; isolectotype K barcode K000227556 [image!]).
= Adiantum decorum T. Moore in Gard. Chron. 1869: 582. 1869. – Lectotype (designated by Tryon 1964: 169, as first step; second step designated here): Cultivated by Veitch, originally from Peru, R. Pearce 502 (K barcode K000633095!; isolectotype: K barcode K000633097!).
= Adiantum cuneatum var. majus Baker in Mart., Fl. Bras. 1(2): 594. 1870. – Lectotype (designated here): Brazil, Santa Catarina, F. Mueller 249 (K barcode K000846870!).
= Adiantum aemulum T. Moore in Gard. Chron., n.s., 8: 584, fig. 114. 1877. – Holotype: Cultivated by Veitch, originally from Brazil, s.coll. (K barcode K000633055!).
= Adiantum cyclosorum T. Moore in Gard. Chron., ser. 3, 1. 547. 1887. – Lectotype (designated here): Cultivated by Veitch, ex Hort. Backhouse 1870, originally from Ecuador, s.coll. (K barcode K000633054!, isolectotype: K barcode K000633053!).
Fig. 7.
Adiantum pseudotinctum – A: habit; B: rhizome scale; C: sterile pinnule; D: detail of segment base; E: fertile pinnule, abaxial view with indusia; F: detail of indusium adaxially. – A. raddianum – G, H: habits; I: rhizome scale; J, K: sterile pinnules; L: detail of segment base; M, N: fertile pinnules, abaxial view with indusia; O: detail of indusium adaxially. – A–F from Hirai & Prado 691 (SP); G, I, K, L, N, O from Hirai & Prado 724 (SP); H, J, M from Prado & Hirai 2037 (SP) – Drawn by Klei Sousa.
= Adiantum cuneatum var. vastum Rosenst. in Hedwigia 43: 217. 1904, ex descriptione. – Type: Brazil, Santa Catarina, Toledo, A. Ulbricht 16 (S n.v.).
= Adiantum werckleanum Christ in Bull. Herb. Boissier, sér. 2, 4: 1093. 1904. – Lectotype (designated by Lellinger 1989: 154, as first step; second step designated here): Costa Rica, 1903, C. Wercklé s.n. (P barcode P00608518 [image!]; isolectotype: P barcode P00608517 [image!]).
= Adiantum cuneatum f. elongatum Rosenst. in Hedwigia 46: 82. 1906, ex descriptione, as “elongata”. – Type: Brazil, Santa Catarina, Blumenau, L. Haerchen 2a (S [n.v.]).
= Adiantum baenitzii Rosenst. in Repert. Spec. Nov. Regni Veg. 5: 230. 1908. – Lectotype (designated by Lellinger 1989: 154): Bolivia, Prov. La Paz, Sud Yungas, Sirupaya prope Yanacachi, 16° lat., 2100 m, ad margines silvarum, 1 Dec 1906, O. Buchtien 462 (UC barcode UC478387 p.p.!; isolectotypes: S05-9806!, US barcode US00142177!, P barcodes P00608523 [image!], P00608522 [image!]).
= Adiantum cuneatum var. subintegrum Hieron. in Hedwigia 48: 240, t. 11, fig. 14. 1909, as “subintegra”. – Holotype: Colombia, Cauca, near Puracé, A. Stübel 112 (B barcode B 20 0003921!).
Morphological description — Plants terrestrial. Rhizomes 4–6 mm in diam., moderately slender, short-creeping, nodose, compact, castaneous, scaly, scales 1.5–3 × 0.2–0.5 mm, linear-lanceolate, dark brown to light brown, concolorous, shiny, basifixed, margins entire, sometimes short ciliate distally, apex acuminate. Fronds closely spaced (to 2 mm apart), laxly arching; stipes 9.5–33 cm × 0.9–2 mm, ⅓–⅔ frond length, dark reddish brown, lustrous, glabrous, with a few scales at base like those of rhizomes; rachis not flexuous, sometimes slightly flexuous, castaneous to red-brown, glabrous; laminae 9.5–33 × 4.5–22 cm, ovate-deltate to ovate-lanceolate, 2–4-pin-nate proximally, 2- or 3-pinnate distally, apex gradually reduced; pinnae 7–13 pairs, stalked, stalk of proximal pinna pair 5–17 mm long, apex gradually reduced, alternate to subopposite; proximal acroscopic pinnule of each pinna not overlapping main rachis; ultimate segments 0.4–2.3 × 0.3–2 cm, stalked, stalk 1.5–3 mm long, non-articulate, with dark colour slightly passing into pinnule base, herbaceous, obovate to flabellate, cuneate at base, apex round, sterile margins dentate, abaxially and adaxially glabrous; veins free, forking, ending in sinuses; sori 1–5 per pinnule, confined to distal margins; indusia 1.5–2 mm wide, reniform to round-reniform, with often deep sinuses, glabrous.
Distribution and ecology — It is the widest distributed species of the group and occurs in montane evergreen and semideciduous forests of Mexico, Guatemala, Nicaragua, Costa Rica, Greater and Lesser Antilles, Colombia, Venezuela, Trinidad, Ecuador, Peru, Brazil, Bolivia, Paraguay, Argentina, Uruguay, naturalized in Paleotropics, Hawaiian Islands; 0–2200 m elevation.
Remarks — Presl (1836) renamed Adiantum cuneatum Willd., because it was an illegitimate name. He called the species as A. raddianum in honour of Giuseppe Raddi (see more details about the story of these names in Pichi Sermolli 2005). Tryon (1964) was the first author to lectotypify A. raddianum, but a second step was necessary and presented here.
Adiantum raddianum is extremely variable in the form (Fig. 7G, H). It is a widely cultivated fern throughout the tropics and subtropics, which escaped from cultivation in many situations and it has become naturalized e.g. in S Africa, New Guinea and Sri Lanka (Goudey 1985), as well as suspected of the same in Guatemala and The Lesser Antilles (Proctor 1985; Mickel & Smith 2004).
Adiantum raddianum is confused with A. lorentzii based on the general aspect of the fronds; see comments under that species for comparison.
Some specimens from Costa Rica appear to be bigger and therefore have already been considered as a distinct species by Christ (1904) named as Adiantum werckleanum, but they overlap morphologically with the concept of A. raddianum. Molecular studies including populations from Costa Rica are necessary to clarify their identification. Unfortunately, Hirai & al. (2016) were unable to include samples in their phylogenetic analyses.
13. Adiantum ruizianum Klotzsch in Linnaea 18: 551. 1844. – Lectotype (designated by Tryon 1964: 175, as first step; second step designated here): Peru, s.loc., s.d., H. Ruíz 26 (B barcode B 20 0007092!; isolectotypes: B barcode B 20 0090400 [fragment]!, NY barcode NY00144571 [fragment]!). – Fig. 8A–F.
= Adiantum veitchianum T. Moore in Gard. Chron. 1868: 1090. 1868 ≡ Adiantum microsorum C. Chr., Index Filic.: 30. 1905, nom. illeg. superfl. – Lectotype (designated by Tryon 1964: 175): Peru, [Huánuco], Munã, R. Pearce s.n. (K barcode K001090121 [image!]).
= Adiantum steerei Harr. in J. Linn. Soc., Bot. 16: 34. 1877. – Lectotype (designated by Tryon 1964: 176): Peru, [Amazonas], Poma Cocha, along streams of water between Myobamba and Chachapovas, Jul 1872, J. B. Steere s.n. (K barcode K000633104!; isolectotypes: GH barcode GH00020382 [image!], P barcode P00608510!, US barcode US00142202 [fragment]!, MICH1259203 [image!], MICH1259543 [image!], MICH1259542 [image!]).
Morphological description — Plants terrestrial. Rhizomes 1.2–2.5 mm in diam., slender, long-creeping, castaneous, scaly, scales 1–1.4 × 0.2–0.3 mm, lanceolate, castaneous to dark brown, concolorous, shiny, basifixed, margins entire, apex apiculate. Fronds distantly spaced ((4–)10–30 mm apart), arching; stipes 14–19 cm × 1–1.7 mm, ⅓–⅔ frond length, dark brown, sublustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis not flexuous, dark brown, glabrous; laminae chartaceous, rarely herbaceous, 8.5–15(–27.7) × 5–7(–18.5) cm, linear-lanceolate, rarely oblong-lanceolate, 1- or 2-pinnate proximally and 1-pin-nate distally, rarely 3-pinnate proximally and 1- or 2-pin-nate distally, apex slightly reduced; pinnae 5–7(–11) pairs, stalked, stalk of proximal pinna pair 21–27 mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna not overlapping main rachis; ultimate segments 1.6–4.2 × 1.3–2.9 cm, long stalked, stalk (2–)9–20 mm long, non-articulate, with dark colour strongly passing into pinnule base, flabellate, truncate to slightly cuneate at base, apex round, sterile margins lobed and denticulate, abaxially and adaxially glabrous; veins free, forking, ending in sinuses of sterile segments; sori 7–19 per pinnule, confined to distal margins; indusia 1–2 mm wide, orbicular to reniform, with deep sinuses, glabrous.
Fig. 8.
Adiantum ruizianum – A: habit; B: rhizome scale; C: sterile pinnule; D: detail of segment base; E: fertile pinnule, abaxial view with indusia; F: detail of indusium adaxially plus sporangia. – A. shepherdii – G: habit; H: sterile frond; I: rhizome scale; J: sterile pinnule; K: detail of segment base with hairs; L: fertile pinnule, abaxial view with indusia; M: detail of indusium adaxially plus sporangia. – A–F from Werff & al. 15339 (MO); G, I–M from Yatskievych & Gastony 86-302 (MO); H from Steinmann 5443 (NY) – Drawn by Klei Sousa.
Distribution and ecology — It can be found in montane forests of Peru and Bolivia; 1600–2900 m elevation.
Remarks — Adiantum ruizianum is easily recognized by long-creeping rhizomes and laminae 1- or 2-pinnate proximally (Fig. 8A), and without yellow-farinose indusia. The specimen collected by Nelson s.n. (P01284122) is unique and atypical in having laminae 3-pinnate proximally and 1- or 2-pinnate distally. But in the other aspect is identical to A. ruizianum.
This species was cited in Brazil by Prado (2010), based on a specimen collected by Salino 182 (GH, UEC). This specimen resembles Adiantum ruizianum in the general aspect of the habit but differs in having erect to short-creeping rhizome, 2-pinnate lamina, and yellow-farinose indusia. These characters are not present in A. ruizianum. The specimen Salino 182 was collected in low elevation (c. 200 m alt.), in the Mato Grosso State, Brazil near the Bolivian border. Adiantum ruizianum grows only in high elevations (c. 1600 m). Perhaps the material Salino 182 could represent an undescribed species of the A. raddianum group. A field trip was carried out by the present authors to the exact locality visited by Salino (Mato Grosso, Cáceres), but the species was not located in the region. More studies are necessary to confirm its identity.
Christensen (1905) created a new name for Adiantum veitchianum T. Moore (A. microsorum), but it is an unnecessary new name as Ballard (1954) has pointed out.
14. Adiantum shepherdii Hook., Sp. Fil. 2: 9, t. 73B. 1851. – Holotype: Mexico, 1834, D. M. Bates s.n. (K barcode K000484003!). – Fig. 8G–M.
Morphological description — Plants terrestrial or rupicolous. Rhizomes c. 4 mm in diam., moderately slender, short-creeping, ± nodose, compact, castaneous, scaly, scales 1.4–2.6 × 0.2–0.3 mm, linear-lanceolate, golden brown to dark brown, concolorous, shiny, basifixed, margins short ciliate, cilia c. 0.2 mm long, tortuous, with same colour as body of scale, apex acute. Fronds closely spaced (2–3 mm apart), arching; stipes 4–10(–11) cm × 1–2 mm, 
–¼(–⅓) frond length, castaneous to dark brown, sublustrous, glabrous or slightly pubescent, with a few scales at base similar in morphology to those of rhizomes, glandular hairs, hyaline to reddish, 0.05–1 mm, 2-celled; rachis not flexuous, castaneous to dark brown, glabrous or slightly pubescent like petioles and with linear scales, sometimes glaucous, scales 1–1.5 mm long, red-brown; laminae coriaceous, 16.5–53 × 1.7–2.8(5.7) cm, linear, 1-pinnate proximally and distally, rarely 2-pinnate proximally, when 2-pinnate ± trifurcate, apex slightly reduced; pinnae 27–55 pairs, stalked, stalk of proximal pinna pair 2–4 mm long, apex gradually reduced, subopposite to alternate, overlapping main rachis; ultimate segments to (0.9–)1.4–2 × (0.4–)0.8–1 cm, sessile or subsessile, up to c. 0.5 mm, non-articulate, with dark colour passing into pinnule base, obliquely flabellate or dimidiate, slightly cuneate at base, apex round, sterile margins entire to broadly crenate or lobate, distinctly thickened, abaxially and adaxially glabrous; veins free, forking, ending at cartilaginous margins; sori 3–8 per pinna, confined mostly to acroscopic and distal margins; indusia 1–2.5 mm wide, orbicular to reniform, with often deep sinuses, glabrous.
Distribution and ecology — It occurs on rocky banks, oak woods, pine-oak forest in Mexico (endemic); 500–1850(–2200) m elevation.
Remarks — As commented by Mickel & Smith (2004), Adiantum shepherdii is characterized by linear fronds with pinnae overlapping the main rachis (Fig. 8H). Yatskievych & Gastony 86-302 (MO), Eggler 177 (NY) and Arsène 117 (UC) are specimens with laminae 2-pinnate proximally, ± trifurcate (Fig. 8G). These specimens resemble A. patens but differ by the glabrous laminar tissue on both lamina surfaces.
Adiantum galeottianum is also an endemic species from Mexico, it is similar to A. shepherdii, but differs by the form of the ultimate segments (suborbicular, subcordate, vs obliquely flabellate or dimidiate).
15. Adiantum subvolubile Mett. ex Kuhn in Linnaea 36: 77. 1869. – Lectotype (designated by Tryon 1964: 167): Ecuador, Azuay, Puente de Baños, R. Spruce 5318 (B barcode B 20 0007283!; isolectotypes: BM barcode BM000777077 p.p.!, GH barcodes GH00020383 [image!], GH000112384 [image!], K barcodes K000656191!, K000656193!, TCD barcode TCD0008562 [image!], NY barcodes NY00564008!, NY00564009!). – Fig. 9A–F.
Morphological description — Plants rupicolous or rarely terrestrial. Rhizomes 2–4 mm in diam., slender, long-creeping, sometimes ± compact and nodose, dark brown, scaly, scales 2–2.3 × 0.2–0.4 mm, lanceolate, castaneous, concolorous, shiny, basifixed, margins entire, apex apiculate. Fronds closely spaced ((2–)5–10 mm apart), arching; stipes (5–)15–23 cm × 0.5–1 mm, ⅙–¼ frond length, castaneous to dark brown, sublustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis ± flexuous or not, castaneous to dark brown, glabrous; laminae herbaceous to chartaceous, 21–55 × (5–)9.5–14 cm, lanceolate to ovate-lanceolate, 2- or 3-pin-nate proximally, 1- or 2-pinnate distally, apex gradually reduced; pinnae 13–21 pairs, stalked, stalk of proximal pinna pair 0.5–1(–3) mm long, rarely furcate, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna overlapping in all main rachis; ultimate segments 0.5–1.6 × 0.6–1.1 cm, subsessile, stalk c. 0.5 (–1) mm long, non-articulate, with dark colour slightly passing into pinnule base or not, obovate to flabellate, cuneate at base, sometimes truncate, apex round, sterile margins entire to lobed and denticulate, abaxially and adaxially glabrous; veins free, forking, ending in sinuses of sterile segments; sori 3–8 per pinnule, confined to distal margins; indusia 1–2.5 mm wide, orbicular to reniform, sometimes suboblong juvenile indusia, with often deep sinuses, yellow-farinose or with glands.
Fig. 9.
Adiantum subvolubile – A: habit; B: rhizome scale; C: sterile pinnule; D: detail of segment base; E: fertile pinnule, abaxial view with indusia; F: detail of indusium detached abaxially with sporangia and yellow-farina. – A. tinctum – G: habit; H: rhizome scale; I: sterile pinnule; J: detail of segment base; K: fertile pinnule, abaxial view with indusia; L: detail of indusia adaxially. – A–D from Correll E334 (NY); E, F from Bohs 2035 (QCA); G–L from McHenry & al. #10-24 (SP). – Drawn by Klei Sousa.
Distribution and ecology — It occurs on and among rocks on steep slopes and on banks along roadsides, on the coastal lomas and mid- to upper-elevations in the Andes; Ecuador and Peru; 250–3000 m elevation.
Remarks — In general Adiantum subvolubile is misidentified as A. concinnum and vice-versa, because both species have the proximal pinnule overlapping the main rachis. As pointed out by Tryon & Stolze (1989), A. concinnum can be distinguished by the furcate stalk of the proximal pinnule (vs simple in A. subvolubile). The fertile specimens of A. subvolubile have yellow-farinose indusia (Fig. 9F), whereas in A. concinnum this character is absent.
The other species closely related to Adiantum subvolubile is A. tinctum, which differs in having the proximal acroscopic pinnule of each pinna stalked and the stalks have (3–)7–20 mm long (vs subsessile, 0.5–1(–3) mm in A. subvolubile, Fig. 9D, E). Furthermore, A. tinctum has not yellow-farina indusia.
16. Adiantum tinctum T. Moore in Gard. Chron. 1862: 932. 1862. – Holotype: Cultivated by Veitch, originally from Peru, s.coll. (K barcode K000633102!). – Fig. 1I, 9G–L.
= Adiantum concinnum var. integrum T. Moore, Index Fil.: 23. 1857, validated by reference to the diagnosis of the unnamed variety “ß” of A. concinnum in Hooker, Sp. Fil. 2: 42. 1851. – Lectotype (designated here): Ecuador, Pichincha, Andes of Quito, W. Jameson 16 (K barcode K000846878 p.p.!).
= Adiantum colpodes T. Moore in Gard. Chron. 1865: 530. 1865. – Lectotype (designated by Tryon 1964: 169, as first step; second step designated here): Cultivated by Veitch, Hort. Chelsea, originally from Ecuador collected by R. Pearce s.n. (K barcode K000633101!; isolectotypes: K barcodes K000633098!, K000633099!, K000633100!).
= Adiantum wagneri Mett. ex Kuhn in Linnaea 36: 77. 1869. – Lectotype (designated here): Ecuador. L. Fraser s.n. (B barcode B 20 0007847 p.p.!).
Morphologicaldescription— Plantsterrestrial, rarely rupicolous. Rhizomes c. 2–4 mm in diam., moderately slender, long-creeping, compact, castaneous, scaly, scales 1.5–3 × 0.3–0.5 mm, lanceolate to linear-lanceolate, castaneous, concolorous, shiny, basifixed, margins entire, apex acuminate. Fronds closely spaced or up to 4 mm apart, arching to pendent; stipes 11–33 cm × 0.5–1 mm, ⅓–½ frond length, dark brown, castaneous to dark brown, lustrous, glabrous, with a few scales at base similar in morphology to those of rhizomes; rachis not flexuous, castaneous to dark brown, glabrous or rarely with scales, filiform, c. 1 mm long; laminae herbaceous, 12.7–32 × 8–20 cm, lanceolate to ovate-lanceolate, 2- or 3-pinnate proximally, 2-pinnate distally, apex gradually reduced; pinnae 6–12 pairs, stalked, stalk of proximal pinna pair (3–)7–20 mm long, apex gradually reduced, alternate; proximal acroscopic pinnule of each pinna often overlapping main rachis distally; ultimate segments 0.7–1.8 × 0.3–2.2 cm, stalked, stalk 0.2–3 mm long, non-articulate, with dark colour stopping slightly at pinnule base, obovate to flabellate, cuneate or attenuate, apex round or slightly crenate, sterile margins denticulate, lobed or incised distally, abaxially and adaxially glabrous; veins free, forking, ending in sinuses of sterile segments; sori 1–9 per pinnule, confined to distal margins; indusia 1–2.1 mm wide, orbicular to reniform, with often deep sinuses, glabrous.
Distribution and ecology — In montane forests of Venezuela, Colombia, Ecuador, Peru and Bolivia; 1500–3400 m elevation.
Remarks — Adiantum tinctum has long-creeping rhizomes, the proximal acroscopic pinnule of each pinna often overlapping the main rachis (Fig. 9G), and grows in high elevations (1500–3400 m). Furthermore, it is quite variable in the morphology of the ultimate segments (oblong to flabellate, cuneate or attenuate), but in general, the apex is round and slightly crenate (Fig. 9K, L). The most similar species is A. subvolubile (see comments of that species) and has been frequently identified as it.
The description and typification for Adiantum concinnum var. integrum T. Moore was provided by Hooker (1851).
Name of uncertain application:
Adiantum lutescens Moug. ex Fée, Mém. Foug. 5, Gen. Filic.: 119. 1852. – Type: Mexico, Oaxaca, s.coll. (Herb. Mougeot, BR?, MPU?). Based on the original description this taxon resembles A. concinnum, but the original material was not located to confirm this assumption.
Specimens of uncertain identity:
Adiantum sp.: Türckheim 870 (US). This material is an old collection from Guatemala, Depart. Alta Verapaz, which resembles A. raddianum, but differs by the presence of glandular hairs above the indusia between sporangia. In all other aspects match with A. raddianum.
Adiantum sp.: Schuettpelz 333 (DUKE). This specimen is originally from Argentina, cultivated at Juniper Level Botanical Garden, North Carolina, and looks like A. raddianum. In the A. raddianum group phylogeny by Hirai & al. (2016) it emerges together with A. raddianum + A. moorei. Its position is uncertain for the moment.
Adiantum sp.: Salino 182 (UEC, GH). See remarks under A. ruizianum.
Acknowledgements
We thank The New York Botanical Garden and Dr. Robbin Moran for providing all facilities during the visit of the first author to the NY herbarium. We thank the curators of B, BHCB, BM, CAY, CORD, DUKE, EAC, ESA, HRCB, INTA, K, LP, LIL, LPB, MBM, MEXU, MO, MCNS, NY, P, QCA, RB, S, SGO, SI, SJRP, SP, SPF, UB, UC, US, UEC, UPF, UPRRP, US, VEN, VT for providing loans and allowing consult their collections, and staff at the DS and GH herbaria for sending specimen images; Dr. Brigitte Zimmer for discussion about the type of Adiantum lorentzii Hieron. and A. cuneatum var. veneris Griseb.; Dr. Marcela Hernández and Olga Martínez for help the second author in field trip in Argentina; Dr. Eric Schuettpelz and Layne Huiet for their help and facilities at Wilmington and Duke University, respectively; Klei Sousa for drawing the plates; and Luciana B. Benatti of the Instituto de Botânica for her help to prepare the SEM images. We also thank Dr. Michael Sundue (VT) and the other, anonymous reviewer for their suggestions to improve this paper. This study was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Proc. n. 2011/07164-3).
