Deble, L. P. & F. S. Alves (2013). Herbertia amabilis Deble & F. S. Alves (Iridaceae), a new species from Brazil. Candollea 68: 133–137. In English, English and French abstracts.
A new species, Herbertia amabilis Deble & F. S. Alves (Iridaceae), is described and illustrated from Rio Grande do Sul State, Brazil. Herbertia Sweet is a predominately South American genus, now comprising 8 species with 7 of them occurring in southern Brazil. Herbertia amabilis is closely related with Herbertia lahue subsp. amoena (Griseb.) Goldblatt, but can be distinguished principally by robust habit, narrowly linear leaves, style arms recurved at the apex, and smaller obovate-clavate ovary. With just two known populations occurring in central Rio Grande do Sul State, with an extent of occurrence comprised in less than 100 km2 and the populations size being smaller than 10 km2 the new species is preliminary considered as critically endangered. The geographic distribution of the new species is presented as well as the key for the Brazilian species of Herbertia.
Introduction
Herbertia Sweet (Iridaceae) is a small genus comprising seven species, occurring on grasslands and stony grasslands in temperate North and South America (Roitman & Castillo, 2008; Deble, 2010). The genus is characterized by the following features: small habit, distinctly dissimilar tepals series, androgynoecium filaments entirely united in a column or free only apically, horizontal or ascending linear anthers, and style branches straight or recurved, each stigmatic and forked apically.
In Brazil, Herbertia is restricted to southernmost portion of the country, in Rio Grande do Sul and southeast Santa Catarina States, where it is represented by the following species: H. crosae Roitman & J. A. Castillo, H. darwinii Roitman & J. A. Castillo, H. lahue subsp. amoena (Griseb.) Goldblatt (= H. fucata (Klatt) Ravenna), H. pulchella Sweet, H. quareimana Ravenna, and H. zebrina Deble.
Herbertia crosae and H. darwinii occur on grasslands and stony grasslands in southwest Rio Grande do Sul, northwest Uruguay and northeast Argentina. Herbertia pulchella grows on stony grasslands in northeast Uruguay and western Rio Grande do Sul. Herbertia quareimana is restricted to grasslands close to the border between Uruguay and Brazil. Herbertia zebrina is narrowly endemic on stony grasslands in a small area in eastern Rio Grande do Sul. Herbertia lahue subsp. amoena displays relatively ample distribution: Argentina, Brazil (Rio Grande do Sul and southeast of Santa Catarina), Uruguay and Paraguay (Ravenna, 1989; Roitman & Castillo, 2004; Roitman & Castillo, 2008; Goldblatt & Manning, 2008; Deble, 2010).
During trips in central areas in Rio Grande do Sul State, Brazil, we found an attractive new species, evidently closely related to the well-known H. lahue subsp. amoena, but with predominately white flowers and larger size. With the addition of this new species, the genus comprises eight species, seven of them occurring in Brazil.
Results
Herbertia amabilis Deble & F. S. Alves, spec, nova (Fig. 1, 2).
Typus: Brazil. Rio Grande do Sul: Júlio de Castilhos, “no campo, entre gramíneas, no solo argiloso, flores brancas”, 29°18′43″S 53°49′39′W, 23.XII.2010, fl. fr., L. P. Deble 12721, A. S. de Oliveira-Deble, J. N. C. Marchiori & F. S. Alves (holo-: SI!; iso-: CTES!, ICN!).
Species nova ab Herbertiae lahue subsp. amoenae affinis, sed magna statura (30–40 cm alta vs 8–15 cm alta), foliis longioribus et anguste linearis (18–35 cm longis, 0.3–0.5 cm latis vs 8–15 cm longis, 0.4–1 cm latis), ovarium obovatoclavatum, 3.5–5 mm longum (versus ob ovato-oblongum, 6–8 mm longum), tepala exteriora albida, (vs coeruleo-violacea), tepala interiora albida et lutea (vs atro-violacea), optime distincta..
Plants up to 30–40 cm high, subterranean stems 10–20 cm long. Bulb ovoid, 18–24 mm wide, sometimes prolonged in a short collar. Leaves 2, plicate, narrowly linear, 18–35 cm long, 0.3–0.5 cm wide. Spathes 2–4, herbaceous, pallid-green, bivalved, two-flowered, pedunculate, peduncles 4–8.5 cm long; lower valve 2.3–3.4 cm long, the upper 3.5–4.5 cm long, both with membranous edges; pedicel filiform, 4–5 cm long. Flowers predominately white, radially symmetrical, 3.5–4 cm diam. Tepals whorls sharply dissimilar: outer tepals obovate, 18–21 mm long, 9–12 mm wide, white, with yellow dots scattered in the proximal half, and a yellow medial stripe at the base; inner tepals oblanceolate, 5–6 mm long, 1.3–1.8 mm wide, white, with a yellow macula in medial portion, apex long attenuate, acuminate, reflexed. Filaments entirely united in a column, 4.2–4.8 mm long, yellowish along the column; anthers linear, yellow, curved at dehiscence, 7–7.5 mm long; pollen yellow. Ovary obovate-clavate, 3.5–5 mm long, 1.8–2.5 mm wide. Style 9–9.5 mm long; style arms channeled, 4.5–5 mm long, at the apex bifid for 1.8–2.2 mm, the divisions divaricate, recurved, apically stigmatic. Capsules broadly oblong-clavate, 9–11 mm long, 4.5–5 mm wide. Seeds oblong to obconical, angular, reddish-brown, epidermis striate, 1.5–2 mm long.
Etymology. — The specific epithet means kind, delicate and refers to the pretty and delicate flowers of the new species.
Distribution and ecology. — Herbertia amabilis is a narrow endemic of central Rio Grande do Sul State, where just two populations are known. Plants grow in grasslands on clay soils in the hydrographic basin of the Guassupi river southwest of Julio de Castilhos city (Fig. 3).
Phenology. — Flowering and fruiting occur during December.
Conservation. — During the review of herbaria, no exsiccates of H. amabilis were found. The only known collections are those made by the authors and here cited. The extent of occurrence of H. amabilis comprises less than 100 km2 and the populations size are smaller than 10 km2; only two populations are know and with few individuals. Furthermore, agriculture, and urban expansion affect directly the range of the species. Due to the rarity, fragmentation of populations, and observed threats, it seems prudent to include H. amabilis in a preliminary status of Critically Endangered category of the IUCN Red List of Endangered plant species according to the following criteria “CR B1, 2a, b; D” (IUCN, 2011).
Taxonomical note. — Herbertia amabilis by its androgynoecium filaments entirely united forming a column, its ascendant style arms, and the size of flowers is most closely related with H. lahue subsp. amoena, but can be segregated by the following features: robust habit (30–40 cm vs 8–15 cm), narrowly linear leaves, with 18–35 cm long, 0.3–0.5 cm wide (vs linear-lanceolate leaves, with 8–15 cm long, 0.4–1 cm wide), style arms at the apex recurved (vs not or slightly recurved), and ovary obovate-clavate, 3.5–5 mm long (vs obovate-oblong, 6–8 mm long). Additionally, the flowers are predominately white (vs blue-violet, rarely white in atypical individuals occurring among normal ones), with a yellow macula in medial portion of inner tepals (vs without yellow macula). Herbertia crosae, another close species differs by purple dots along the column of androgynoecium filaments (vs without purple dots), free apically up to 1 mm long (vs entirely united), and smaller anthers (4–5 mm vs 7–7.5 mm long). Herbertia darwinii has androgynoecium features similar with the new species, but its differs by large 4–5.7 cm wide, blue-violet flowers, ovary 6– 8.5 mm long, and leaves 1–2 cm wide.
Paratypus. — Brazil. Rio Grande do Sul: Júlio de Castilhos, “no campo, entre gramíneas, no solo argiloso, flores brancas”, 29°18′43″S 53°49′39″W, 23.XII.2010, fr, L. P. Deble 12722, A. S. de Oliveira-Deble, J. N. C. Marchiori & F. S. Alves (CTES !).
Fig. 1.
Herbertia amabilis Deble & F. S. Alves. A. Plant; B. Spathe with flower; C. Spathe with capsules; D. Lateral view of flower; E. Flower with tepals removed showing the androgynoecium; F. Inner tepals; G. Capsule; H. Seeds; I. Medial portion of leaf; J. Apical portion of leaf. [Deble 12721 & al, S1] [Drawn by L. Paz Deble]
Fig. 2.
Herbertia amabilis Deble & F. S. Alves. A. Lateral view of flower; B. Upper view of flower; C. Flower, capsules and general habit; D. Distal portion showing spathe with flower and capsules. [Deble 12721 & al., SI] [Photos: L. Paz Deble]
Key to the Brazilian species of Herbertia:
1. Inner tepals white and dark purple striped, apex rounded to truncate. Anthers less than 3 mm long. Flowers white H. zebrina
1a. Inner tepals not striped, apex obtuse to acuminate. Anthers 4 mm long or more. Flowers pale lilac, violet or blue, rarely white 2
2. Androgynoecium filaments free for 3–5 mm long at the apex. Flowers blue or blue-violet. Outer tepals with a white to light blue streak H. pulchella
2a. Androgynoecium filaments entirely united, forming a column or free up to 2 mm long at the apex. Flowers white, pale violet, blue-violet or violet, without a white to light blue streak 3
3. Flowers white or pale lilac. Outer and inner tepals with a yellow stripe at the base. Ovary 3.5–5 mm long 4
3a. Flowers blue-violet or violet. Outer tepals whitish and dark violet spotted at the base. Inner tepals dark violet, without a yellow stripe at the base. Ovary 6–8.5 mm long 5
4. Plant 8–22 cm high. Leaves 4–5 cm long. Anthers 4–5 mm long H. crosae
4a. Plant 30–40 cm high. Leaves 18–35 cm long. Anthers 7– 7.5 mm long H. amabilis
5. Flowers 55–65 mm wide. Outer tepals without a yellow medial stripe at the base. Androgynoecium filaments free for 1-1,5(-2) mm long at the apex H. quareimana
5a. Flowers 30–55 mm wide. Outer tepals with a yellow medial stripe at the base (rarely absent). Androgynoecium filaments entirely united, forming a column; anthers attached directly to the filament column 6
6. Leaves 10–20 mm wide. Style arms channeled, secondary divisions recurved H. darwinii
6a. Leaves 4–10 mm wide. Style arms not channeled, secondary divisions straight H. lahue subsp. amoena
Acknowledgements
We thank Anabela Deble and José Newton Marchiori for their companionship during the trip in central Rio Grande do Sul, and Benoît Loeuille for the French abstract. We are also grateful to two anonymous referees for valuable comments on the manuscript.
