Introduction

The ferns and fern allies of Rwanda have received little attention. The only more detailed list providing localities was that by Pichi Sermolli (1983, 1985). Since then, only Roux (2009) published an updated list for all countries of Africa including Madagascar, albeit without reference to the single records.

During the preparation of an illustrated field guide of ferns and fern allies for Rwanda, including descriptions and keys for all taxa, the authors recorded numerous species as new country records and six species new to science, as well as two varieties previously not validly published. Two new species are already described, one in a paper on Isoetes in Central Africa (Fischer & Lobin 2022) and one Dryopteris species in a treatment of the exindusiate Dryopteris species from Central Africa (Fischer & Lobin 2023a). A further three new Asplenium species and a synoptic revision of the genus in Rwanda, as well as an overview of Diplazium with the description of a new species, have recently been published (Fischer & Lobin 2023b, 2023c).

The aim of the present publication is to provide the first checklist of all fern and clubmosses species recorded for Rwanda and the formal description of Pleopeltis macrocarpa var. dichotoma Eb. Fischer & Lobin and P. macrocarpa var. pinnatiloba Eb. Fischer & Lobin.

Material and methods

The present checklist is based on an evaluation of the existing literature, herbarium studies in the following herbaria: B, BR, FI, K (abbreviations after Thiers 2022+), and fieldwork between 1984 and 2022. The authors have tried to verify all historic records, mainly from Brause (1910), Brause & Hieronymus (1910) and Pichi Sermolli (1983, 1985).

Results and Discussion

History of pteridological exploration of Rwanda

Until 1907, the flora and fauna of Rwanda were almost unknown to science. During the expedition of Graf von Götzen in 1894 (Götzen 1895) no ferns appear to have been collected in Rwanda, although he listed a few fern collections from the ascent of Mt Nyiragongo, part of the Virunga massif in eastern Democratic Republic of Congo (D. R. Congo). Richard Kandt (see Bindseil 2008), who lived in Rwanda as a private naturalist from 1898–1902, 1905–1907, and later as the Imperial Resident for Rwanda until 1913, made some botanical collections, but only of flowering plants. In 1907 Adolf-Friedrich Herzog zu Mecklenburg embarked on an expedition with the intention of exploring Rwanda and the eastern Belgian Congo. He was accompanied by the geologist Egon von Kirschstein, botanist Johannes Mildbraed, zoologist Hermann Schubotz, anthropologist Jan Czekanowski, Lieutenant and cartographer Max Weiss, physician and bacteriologist W. von Raven, as well as Lieutenant Walter von Wiese und Kaiserwaldau, Friedrich Weidemann, Sergeant Czeczatka and 25 Askari (Herzog zu Mecklenburg 1909). They travelled by train to Lake Victoria and trekked to northeastern Rwanda, where they collected at Lake Mohasi (see Bamps 1975). Having visited the court of King Yuhi V. Musinga at Niansa, Mildbraed and Schubotz left the expedition for about two weeks in order to collect plants and animals in the Nyungwe forest (= Rugege Wald). By March 1908, Mildbraed had visited Lake Kivu and the Virunga Volcanoes, followed by the eastern Congo (Ituri, Aruwimi) and the Ruwenzori mountains. In May 1908 the expedition party travelled down the river Congo by steamboat until they reached the western coast of Africa. They arrived in Hamburg on 30^th June 1908. The scientific results, including zoology, were not published until 1925. The botanical volume, edited by Mildbraed (1910) covered 718 pages. The ferns and fern allies were studied by Brause (1910), Brause & Hieronymus (1910) and Hieronymus (1910). The lycophytes were identified by Herter. The authors recognized 116 species collected during the expedition, among them 12 new species and one new variety. They recorded 47 species for Rwanda, five of them described as new (see Table 3). Their treatment would remain a classic work and, for almost 70 years, the only account for Rwanda and D. R. Congo (former Zaïre).

The next comprehensive work on the ferns was compiled by Pichi Sermolli (1983, 1985). He published an overview of the ferns of eastern D. R. Congo, Rwanda and Burundi. In these papers, he listed all available collections from the region, except those of Mildbraed, and the account is based on his own collections from 1956 and on those from researchers who mostly worked in the area between 1956 and 1982. Pichi Sermolli himself collected only for a few weeks in Rwanda, mainly in the Nyungwe Forest. But he included in his work many collections from various collectors. He described 15 new species, nine of them from Rwanda (see Table 3). In total, Pichi Sermolli recorded 112 species from Rwanda. He was aware of the outstanding botanical and zoological diversity of the region and stated that the Albertine Rift was poorly studied.

While a Flora for the seed plants of the Albert National Park (today Parc National des Virunga in D. R. Congo and Volcano National Park in Rwanda) was published by Robyns (1947, 1948) and Robyns & Tournay (1955), nothing was available for the ferns. In 1945 Taton produced a handwritten manuscript for the ferns of this national park, but it was never published (Bamps 1990). The French botanist H. Humbert was the first to collect on Mt Kahuzi and Mt Biéga in 1929, and also visited the Virunga volcanoes. A. R. Christiaensen, a private researcher associated with the Institut de Recherche Scientifique en Afrique Centrale (IRSAC), collected ferns in Rwanda between 1955 and 1957.

After the independence of Rwanda and D. R. Congo (then Zaïre), several botanists continued to work in this phytogeographically interesting region. From December 1971 to March 1972 and in 1974, the members of the “Mission des Volcans”, P. H. Auquier, P. Bamps, J. E. J. Lambinon, and P. Van der Veken collected in the Nyungwe (= Rugege) Forest and on the volcanoes in Rwanda. They also made extensive collections on Mt Kahuzi, Mt Biéga and around the Irangi Station in D. R. Congo. G. Bouxin and M. Radoux collected in Akagera National Park between 1969 and 1970, and G. Bouxin made collections of ferns between 1970 and 1972 in Nyungwe Forest. During botanical explorations for the “Flore du Rwanda, Spermatophytes” (Troupin 1978, 1983, 1985, 1988), G. Troupin also collected ferns, mainly between 1956 and 1982. Since 1969, single volumes on ferns of the Flore d'Afrique Centrale (previously Flore du Congo du Rwanda et du Burundi) have appeared. Until now only volumes of ferns dealing with smaller families have been published (Actiniopteridaceae: Lawalrée 1969a, Azollaceae: Lawalrée 1976, Blechnaceae: Lawalrée 1971, Davalliaceae: Lawalrée 1993, Equisetaceae: Lawalrée 1969b, Lindsaeaceae: Kramer 1971, Lycopodiaceae: Lawalrée 1989, Marsileaceae: Launert 1975, Nephrolepidaceae: Lawalrée 2000, Osmundaceae: Lewalle 1973, Parkeriaceae: Lawalrée 1969c, Psilotaceae: Lawalrée 1969d, Schizaeaceae: Lawalrée 1970). Only in the treatment of Selaginellaceae (Bizzari 1985) was a larger number of 23 taxa included. Therefore, until now a total of 74 fern species from Central Africa (D. R. Congo, Rwanda, Burundi) have been subject to taxonomic treatment.

Kornaś & al. (1993) provided a distribution atlas of the ferns and fern allies of Rwanda based on the collections published by Pichi Sermolli (1983, 1985) and those of K. A. Nowak. The latter, a priest, lived in Rwanda from 1978 to 1984 and collected ferns in his spare time over almost all Rwanda (Kornaś & Nowak 1991). Seven species were mentioned for the first time for Rwanda. The majority of his specimens are deposited in Krakow (KRA) with duplicates in Meise (BR). Dzwonko & Kornaś (1994) analysed the distribution patterns and diversity of Rwandan ferns.

From 1984 to 2022 the first author (EF) studied the flora and vegetation of Rwanda and eastern D. R. Congo. He was among the first to collect in remote sites and botanically undercollected regions (e.g. Cyamudongo Forest, Busaga Forest, Kagitumba, Ibanda Makera etc.). He found 39 taxa for the first time in Rwanda, among them six species (see Table 3). 24 species are recorded for the first time in this checklist. The other 10 new records and the six new species have been published elsewhere.

Fig. 1.

Cystopteris diaphana, E. Fischer s.n. – A, B: habit; C: frond, adaxial view; D: frond, abaxial view. – A–D: Rwanda, foot of Mt Bisoke, 22 Sep 2022, photographs by and © Eberhard Fischer. – Scale bars: A = 5 cm; B–D = 1 cm.

Table 1.

Species number, species/area ratio and endemics of clubmosses, quillworts and ferns of continental African countries (including Cape Verde and islands of Gulf of Guinea).

Checklist

The taxa are arranged in systematic order after PPG (2016), and Wei & Zhang (2022). For the first records, we cite the name under which the relevant author published it. Misidentifications are recognizable by “auct. non”, synonyms bear full authors citations. New records for Rwanda are marked with “+” before the species name.

The Checklist contains 208 species and two varieties. The most species-rich fern-genus in Rwanda is Asplenium with 44 species (almost every fifth species is an Asplenium), followed by Pteris (11 species) and Dryopteris (10 species out of 26 recorded by Roux (2012) for the whole African continent).

In Rwanda the exploration of the pteridological flora had three major periods: at the beginning of the 20^th century, culminating with the collections from Mildbraed (Mildbraed 1910), a second period in the 1950s with the main collector Pichi Sermolli (Pichi Sermolli 1983, 1985), and a third, from 1984 until today mainly with the collections from the first author, Eberhard Fischer. An enumeration of the number of species mentioned by the above cited collectors for the first time for Rwanda is found in Table 3.

Lycopodiopsida

Isoetaceae

Isoetes rwandensis Eb. Fisch. & Lobin

First recorded — Fischer & Lobin (2022: 332).

Endemic status — Local endemic.

Lycopodiaceae

Huperzioideae

Phlegmariurus afromontanus (Pic. Serm.) A. R. Field & Bostock

First recorded — Pichi Sermolli (1983: 183) as Huperzia afromontana Pic. Serm.

Endemic status — Albertine Rift endemic.

Phlegmariurus bampsianus (Pic. Serm.) A. R. Field & Bostock

First recorded — Pichi Sermolli (1985: 193) as Huperzia bampsiana Pic. Serm.

Endemic status — Local endemic.

Phlegmariurus gnidioides (L. f.) A. R. Field & Bostock

First recorded — Pichi Sermolli (1983: 184) as Huperzia gnidioides L. f.

Phlegmariurus mildbraedii (Herter) A. R. Field & Bostock

First recorded — Brause (1910: 38) (determination W. Herter) as Lycopodium mildbraedii Herter.

Phlegmariurus saururus (Lam.) B. Øllg.

First recorded — Brause (1910: 38) (determination W. Herter) as Lycopodium saururus Lam.

Phlegmariurus verticillatus (L. f.) A. R. Field & Testo

First recorded — Pichi Sermolli (1983: 185) as Huperzia verticillata (L. f.) Trevis.

Lycopodielloideae

Palhinaea cernua (L.) Carv. Vasc. & Franco

First recorded — Brause (1910: 39) (determination W. Herter) as Lycopodium capillaceum (Willd. ex Spring) Willd. ex Spring.

Pseudolycopodiella affinis (Bory ex Willd.) Holub

First recorded — Brause (1910: 39) (determination W. Herter) as Lycopodium carolinianum auct. non L.

Note — Although already mentioned by Brause (1910) (J. Mildbraed 968, B 20 0109407 [https://herbarium.bgbm.org/object/B200109407]), this species has been overlooked by recent researchers (e.g. Roux 2009).

Lycopdioideae

Lycopodium clavatum L.

First recorded — Brause (1910: 39) (determination W. Herter) as Lycopodium trichophyllum auct. non Desv.

Selaginellaceae

+Selaginella caffrorum (Milde) Hieron.

New record — Rwanda: Eastern Province: Nyarubuye, Rugarama, quartzitic rocks on sun-exposed rock faces, 02°09′16.12″S, 30°42′56.19″, 1743 m, 10 Apr 2005, E. Fischer s.n. (KOBL); Nyarubuye, 02°08′54.74″S, 30°45′00.37″E, 1749 m, 30 Mar 2014, E. Fischer s.n. (KOBL).

Selaginella goudotana Spring

First recorded — Bizzarri in Pichi Sermolli (1983: 188) as Selaginella goudotana var. abyssinica (Spring) Bizzarri.

Selaginella kraussiana (Kunze) A. Br.

First recorded — Hieronymus (1910: 40).

Selaginella lewalleana Bizzarri

First recorded — Bizzarri (1981: 222).

Endemic status — Albertine Rift endemic.

+Selaginella mittenii Baker

New record — Rwanda: Western Province: Nyungwe NP, Cyamudongo Forest, wet rocks in montane forest, 02°33′04.03″S, 28°59′48.58″E, 1732 m, 6 Sep 2017, E. Fischer s.n. (KOBL).

Selaginella soyauxii Hieron.

First recorded — Bizzarri in Pichi Sermolli (1983: 189).

+Selaginella tenerrima A. Br. ex Kuhn

New record — Rwanda: Western Province: Nyungwe NP, Cyamudongo Forest, Forest floor or on wet rocks near streams and waterfalls in montane forest, 1732 m, 02°33′04.03″S, 28°59′48.58″E, 4 Apr 2021, E. Fischer s.n. (KOBL).

Note — Roux (2009: 28) listed Rwanda under Selaginella tenerrima, albeit without mentioning a published record. Bizzari (1985) has recorded the species only in D. R. Congo and Burundi. Therefore, our collections from Rwanda represent the first definite record of the species.

Polypodiopsida

Ophioglossidae

Ophioglossaceae

Ophioglossum costatum R. Br.

First recorded — Brause (1910: 38) as Ophioglossum fibrosum Schumach.

Fig. 2.

Cystopteris diaphana, E. Fischer s.n. – A, B: pinnules, showing veins ending in sinuses between teeth (arrows); C, D: SEM micrographs of spores. – Cystopteris fragilis, E. Fischer s.n. – E, F: SEM micrographs of spores. – A–D: Rwanda, foot of Mt Bisoke, 22 Sep 2021, photographs by and © Eberhard Fischer (A, B) and by Eberhard Fischer, Wolfram Lobin and Yaron Malkowsky (C, D). – E, F: Germany, Koblenz, photographs by Eberhard Fischer, Wolfram Lobin and Yaron Malkowsky. – Scale bars: A, B = 5 mm; C, E = 10 µm; D, F = 8 µm.

+Ophioglossum thomasii R. T. Clausen

New record — Rwanda: Northern Province: W Mukamira S of Bigogwe, granitic outcrops, 01°38′45.56″S, 29°23′37.08″E, 2425 m, Oct 1989, E. Fischer s.n. (KOB).

Ophioglossum vulgatum subsp. africanum Pocock ex J. E. Burrows

First recorded — Pichi Sermolli (1983: 193) as Ophioglossum vulgatum L.

Marattiidae

Marattiaceae

Ptisana africana Christenh.

First recorded — Brause (1910: 37) as Marattia fraxinea auct. non Sm.

Polypodiidae

Anemiaceae

Anemia lepigera (Baker) Christenh.

First recorded — Pichi Sermolli (1983: 209) as Mohria lepigera (Baker) Baker.

Aspleniaceae

Asplenium abyssinicum Fée

First recorded — Pichi Sermolli (1985: 125).

Asplenium adiantum-nigrum L.

First recorded — Fischer & Lobin (2023c: 9).

Asplenium aethiopicum (N. L. Burm.) Becherer subsp. aethiopicum

First recorded — Brause & Hieronymus (1910: 19) as Asplenium furcatum Thunb.

Asplenium africanum Desv.

First recorded — Fischer & Lobin (2023c: 9).

Asplenium boltonii Hook. ex Schelpe

First recorded — Fischer & Lobin (2023c: 9).

Asplenium bugoiense Hieron.

First recorded — Hieronymus in Brause & Hieronymus (1910: 10).

Asplenium burundense Pic. Serm.

First recorded — Fischer & Lobin (2023c: 10).

Endemic status — Albertine Rift endemic.

Asplenium cancellatum Alston

First recorded — Fischer & Lobin (2023c: 10).

Asplenium ceii Pic. Serm.

First recorded — Brause & Hieronymus (1910: 12) as Asplenium loxoscaphoides auct. non Baker.

Asplenium centrafricanum Pic. Serm.

First recorded — Brause & Hieronymus (1910: 12) as A. sertularioides auct. non Baker.

Endemic status — Albertine Rift endemic.

Asplenium christii Hieron.

First recorded — Fischer & Lobin (2023c: 14).

Asplenium dregeanum Kunze

First recorded — Pichi Sermolli (1985: 131) as Asplenium dregeanum subsp. brachypterum (Kunze ex Houlst. & T. Moore) Pic. Ser.

Asplenium elliottii C. H. Wright

First recorded — Brause & Hieronymus (1910: 8) as Asplenium chlaenopteron auct. non Fée.

Asplenium erectum Bory ex Willd.

First recorded — Pichi Sermolli (1985: 133) as Asplenium erectum var. usambarense (Hieron.) Schelpe.

Asplenium friesiorum C. Chr.

First recorded — Brause & Hieronymus (1910: 16) as Asplenium decrescens auct. non Kunze.

Asplenium gemmascens Alston

First recorded — Pichi Sermolli (1985: 135).

Asplenium hypomelas Kuhn

First recorded — Pichi Sermolli (1985: 123) as Loxoscaphe nigrescens T. Moore.

Asplenium inaequilaterale Willd.

First recorded — Fischer & Lobin (2023c: 19).

Asplenium linckii Kuhn

First recorded — Pichi Sermolli (1985: 143).

Asplenium lividum Mett.

First recorded — Fischer & Lobin (2023c: 19).

Asplenium loxoscaphoides Baker

First recorded — Brause & Hieronymus (1910: 12).

Asplenium majus (Hieron.) Pic. Serm.

First recorded — Brause & Hieronymus (1910: 19) as Asplenium goetzei var. majus Hieron. in Brause & Hieronymus (1910: 8).

Asplenium mannii Hook.

First recorded — Pichi Sermolli (1985: 144).

Asplenium markusbeckeri Eb. Fisch. & Lobin

First recorded — Fischer & Lobin (2023c: 24).

Endemic status — Albertine Rift endemic.

Fig. 3.

Habit of Pleopeltis macrocarpa var. dichotoma, E. Fischer s.n. – A: Rwanda, Mt Gahinga, 20 Mar 2022, photograph by and © Eberhard Fischer; B–D: Germany, in cultivation in Botanical Gardens Bonn, photographs by and © Eberhard Fischer and Wolfram Lobin. – Scale bars: A, B = 1 cm.

Asplenium megalura Hieron.

First recorded — Pichi Sermolli (1985: 144).

Asplenium mildbraedii Hieron.

First recorded — Hieronymus in Brause & Hieronymus (1910: 21).

Asplenium monanthes L.

First recorded — Brause & Hieronymus (1910: 15).

Asplenium musiraense Viane

First recorded — Pichi Sermolli (1985: 127) as Asplenium buettneri auct. non Hieron.

Endemic status — Albertine Rift endemic.

Asplenium normale D. Don

First recorded — Pichi Sermolli (1985: 146).

Asplenium preussii Hieron.

First recorded — Pichi Sermolli (1985: 147) as Asplenium pseudoauriculatum Schelpe.

Asplenium protensum Schrad.

First recorded — Brause & Hieronymus (1910: 16).

Asplenium ramicola Eb. Fisch. & Lobin

First recorded — Fischer & Lobin (2023c: 35).

Endemic status — Local endemic.

Asplenium rukaraense Hieron.

First recorded — Hieronymus in Brause & Hieronymus (1910: 12).

Endemic status — Albertine Rift endemic.

Asplenium rutifolium (P. J. Bergius) Kunze

First recorded — Pichi Sermolli (1985: 152) as Asplenium strangeanum Pic. Serm.

Asplenium sandersonii Hook.

First recorded — Brause & Hieronymus (1910: 15).

Asplenium sertularioides Baker

First recorded — Brause & Hieronymus (1910: 12).

Asplenium smedsii Pic. Serm.

First recorded — Pichi Sermolli (1985: 152).

Asplenium stuhlmannii Hieron.

First recorded — Pichi Sermolli (1985: 152).

Asplenium tenuicaudatum Pic. Serm.

First recorded — Pichi Sermolli (1985: 153).

Endemic status — Albertine Rift endemic.

Asplenium theciferum var. concinnum (Schrad.) Schelpe

First recorded — Pichi Sermolli (1985: 124) as Loxoscaphe thecifera var. concinna (Schrad.) Kuhn.

Asplenium trichomanes subsp. quadrivalens D. E. Mey.

First recorded — Fischer & Lobin (2023c: 46).

Asplenium uhligii Hieron.

First recorded — Pichi Sermolli (1985: 136) as Asplenium kassneri auct. non Hieron.

Asplenium uschiae Eb. Fisch. & Lobin

First recorded — Fischer & Lobin (2023c: 50).

Endemic status — Albertine Rift endemic.

Asplenium volkensii Hieron.

First recorded — Pichi Sermolli (1985: 153).

Hymenasplenium kenyense Li Bing Zhang, K. W. Xu & Kamau

First recorded — Fischer & Lobin (2023c: 57).

Athyriaceae

Athyrium newtonii Baker

First recorded — Pichi Sermolli (1985: 154) as Athyrium scandicinum auct. non (Willd.) C. Presl.

Athyrium schimperi Moug. ex Fée

First recorded — Pichi Sermolli (1985: 155).

Deparia boryana (Willd.) M. Kato

First recorded — Pichi Sermolli (1985: 155) as Dryoathyrium boryanum (Willd.) Ching.

Diplazium cyamudongense Eb. Fisch. & Lobin

First recorded — Fischer & Lobin (2023b: 170).

Endemic status — Local endemic.

Diplazium humbertii (C. Chr.) Pic. Serm.

First recorded — Pichi Sermolli (1985: 155).

Endemic status — Albertine Rift endemic.

Diplazium zanzibaricum (Baker) C. Chr.

First recorded — Kornaś & Nowak (1991: 12).

Blechnaceae

Lomaridium attenuatum (Sw.) Gasper & V. A. O. Dittrich

First recorded — Pichi Sermolli (1985: 191) as Blechnum giganteum (Kaulf.) Schltdl.

Lomariocycas tabularis (Thunb.) Gasper & A. R. Sm.

First recorded — Brause & Hieronymus (1910: 27) as Blechnum tabulare (Thunb.) Kuhn.

Cyatheaceae

Alsophila dregei (Kunze) R. M. Tryon

First recorded — Pichi Sermolli (1983: 254).

Fig. 4.

Pleopeltis macrocarpa var. pinnatiloba, E. Fischer s.n. – A, B, D: habit; C: frond. – A–C: Rwanda, Mt Gahinga, 20 Mar 2022 (A), 5 Oct 2006 (B, C), photographs by and © Eberhard Fischer; D: Germany, in cultivation in Botanical Gardens Bonn, photograph by and © Wolfram Lobin. – Scale bars: A = 5 cm; B–D = 1 cm.

Alsophila manniana (Hook.) R. M. Tryon

First recorded — Brause (1910: 1) as Cyathea engleri Hieron.

Cystopteridaceae

Cystopteris diaphana (Bory) Blasdell.

First recorded — Brause & Hieronymus (1910: 2) mentioned Cystopteris fragilis auct. non (L.) Bernh., but this was overlooked by recent researchers (e.g. Roux 2009). Note — Cystopteris diaphana [= C. viridula (Desv.) Desv.] according to Lobin (1986), is distinguished by the veins ending in sinuses between the teeth (vs ending in apices of teeth in C. fragilis) and the spiny-lacunar spores, so densely covered with spines that they obscure the surface (vs echinate spores loosely covered with spines in C. fragilis) (Fig. 1, 2). He recorded the species for the Canary Islands.

Fraser-Jenkins (1986) made the first record for the African mainland (Cameroon). A description of C. viridula with comparison to C. fragilis is also provided by Murphy & Rumsey (2005). Verdcourt (2003: 5) distinguished two subspecies of C. fragilis. His “subspecies B” exactly matches the key characters of C. diaphana. Roux (2009) followed Verdcourt's taxonomic view (2003) and listed “subspecies B” from Algeria, Morocco, Cameroon, Sudan, Ethiopia, Uganda, Kenya, Lesotho and South Africa. All records probably belong to C. diaphana but need verification by spore characters. According to Roux (2009), this species is known only from the Comoro Islands and Réunion. The author also erroneously placed C. viridula as a synonym of C. fragilis. Here we provide the first definite record of C. diaphana for Central Africa.

Davalliaceae

+Davallia chaerophylloides (Poir.) Steud.

New record — Rwanda: Western Province: Rubavu (= Gisenyi), epiphyte on oil palm, 01°42′11.62″S, 29°15′32.15″E, 1472 m, 4 Oct 2022, E. Fischer s.n. (KOBL).

Dennstaedtiaceae

Blotiella bouxiniana Pic. Serm.

First recorded — Pichi Sermolli (1983: 262).

Endemic status — Albertine Rift endemic.

Blotiella glabra (Bory) R. M. Tryon

First recorded — Brause & Hieronymus (1910: 31) as Lonchitis pubescens Willd.

Histiopteris incisa (Thunb.) J. Sm.

First recorded — Pichi Sermolli (1983: 261).

Hypolepis rugosula subsp. pichi-sermolliana Schwartsb. & J. Prado

First recorded — Pichi Sermolli (1983: 258) as Hypolepis rugosula var. africana C. Chr.

Note — Schwartsburd & Prado (2014) revised the difficult species complex Hypolepis rugosula and separated 15 geographically distinct subspecies.

Hypolepis sparsisora (Schrad.) Kuhn

First recorded — Pichi Sermolli (1983: 260).

Microlepia speluncae (L.) T. Moore

First recorded — Brause & Hieronymus (1910: 6).

Note — Kornaś & Nowak (1991) claim this species as a new record for the Flora of Rwanda, overlooked the above citation.

Pteridium aquilinum subsp. capense (Thunb.) C. Chr.

First recorded — Pichi Sermolli (1983: 260) as Pteridium aquilinum (L.) Kuhn subsp. aquilinum.

+Pteridium centrali-africanum (Hieron.) Alston

New record — Rwanda: Eastern Province: rocky savanna N of Karembo, 02°05′58.82″S, 30°26′45.86″E, 1389 m, 8 Dec 2021, E. Fischer s.n. (KOBL).

Note — Thomson & al. (2005) and Roux (2009: 112) cited Rwanda among the distribution records. However, we could not find any earlier record for the country, and neither Thomson & al. (2005) nor Roux (2009) cited any sources. Our collection is apparently the first record.

All Pteridium specimens from Meise (BR) collected in Rwanda, three of which were misidentified as Pteridium aquilinum var. africanum (Bonap.) R. M. Tryon (= P. centraliafricanum), are P. aquilinum subsp. capense. The latter taxon is found in montane forests on open ground and clearings, while P. centraliafricanum is restricted to grassland and dry forests.

Didymochlaenaceae

Didymochlaena spinulosa (Brause) Li Bing Zhang & H. Shang

First recorded — Pichi Sermolli (1985: 176) as Didymochlaena truncatula auct. non (Sw.) J. Sm.

Note — Shang & Zhang (2023) published a revision of the formerly monotypic genus Didymochlaena and recognized 22 species.

Dryopteridaceae

Dryopteridoideae

Arachniodes webbiana subsp. foliosa (C. Chr.) Gibby & al.

First recorded — Pichi Sermolli (1985: 175) as Arachniodes foliosa (C. Chr.) Schelpe.

Dryopteris antarctica (Baker) C. Chr.

First recorded — Pichi Sermolli (1985: 157) as Dryopteris callolepis C. Chr.

Dryopteris athamantica (Kunze) Kuntze

First recorded — Pichi Sermolli (1985: 157).

Dryopteris fadenii Pic. Serm.

First recorded — Roux (2012: 48).

Dryopteris kilemensis (Kuhn) Kuntze

First recorded — Pichi Sermolli (1985: 157).

Note — Kuhn (1868: 24) called his new species Aspidium kilmense and cited as collection “Kilma”. Kunze (1891: 813) placed it in Dryopteris as D. kilmensis (not “kilemensis” as Roux [2009: 122] states). In his checklist, Roux (2009: 122) listed the species as D. kilemensis. However, in his monograph Roux (2012: 63) again named it D. kilmensis, following Kuhn (1868).

Kuhn (1868: 24) and Roux (2012: 122) gave the type locality as “Kilma”. We have checked the holotype in B (B 20 0051628!), where the collectors Von der Decken & Kersten clearly wrote “Kilema ad radices montis Kilimandjaro”. Therefore, the species name must be D. kilemensis.

+Dryopteris lewalleana Pic. Serm.

New record — Rwanda: Western Province, Nyungwe NP, Cyamudongo Forest, terrestrial in montane forests, 2003 m, 02°32′29.33″S, 28°59′06.56″E, 3 Apr 2021, E. Fischer s.n. (KOBL); Nyungwe NP, Cyamudongo Forest, terrestrial in montane forests, 1991 m, 02°33′32.58″S, 28°59′04.86″E, 18 Sep 2021, E. Fischer s.n. (KOBL).

Note — Dryopteris lewalleana was described from Burundi, where it occurred in the Kibira National Park. This NP is the continuation of Nyungwe NP in Rwanda, where it was found recently.

Dryopteris manniana (Hook.) C. Chr.

First recorded — Pichi Sermolli (1985: 163).

Dryopteris pentheri (Krasser) C. Chr.

First recorded — Brause & Hieronymus (1910: 3) as Dryopteris filixmas var. elongata sensu Brause & Hieronymus non D. elongata auct. non (Sw.) Sim.

Dryopteris ruwenzoriensis C. Chr. ex Fraser-Jenkins

First recorded — Roux (2012: 97).

Endemic status — Albertine Rift endemic.

Dryopteris schimperiana (Hochst. ex A. Br.) C. Chr.

First recorded — Roux (2012: 101).

Dryopteris schizopaleata Eb. Fisch. & Lobin

First recorded — Fischer & Lobin (2023a: 138).

Endemic status — Local endemic.

Dryopteris squamiseta (Hook.) Kuntze

First recorded — Pichi Sermolli (1985: 156) as Nothoperanema squamisetum (Hook.) Ching.

Polystichum transvaalense N. C. Anthony

First recorded — Roux (2000: 51).

Polystichum wilsonii Christ

First recorded — Brause & Hieronymus (1910: 4) as Polystichum aculeatum auct. non (L.) Roth.

Note — Roux (2000: 56) did not list Rwanda in his “Distribution”, but in his paragraph “without exact locality”, he listed a specimen from “Karisimbi (versant sud) nr. Biuri, c. 3000 m, De Witte 1246 (BR)”, which is a locality in Rwanda.

Elaphoglossoideae

Elaphoglossum acrostichoides (Hook. & Grev.) Schelpe

First recorded — Pichi Sermolli (1985: 180).

Elaphoglossum aubertii (Desv.) T. Moore

First recorded — Pichi Sermolli (1985: 181).

Elaphoglossum conforme (Sw.) J. Sm.

First recorded — Pichi Sermolli (1985: 181).

Elaphoglossum deckenii (Kuhn) C. Chr.

First recorded — Pichi Sermolli (1985: 181).

Elaphoglossum hybridum (Bory) Brack.

First recorded — Pichi Sermolli (1985: 181).

Elaphoglossum kivuense Schelpe

First recorded — Pichi Sermolli (1985: 182).

Endemic status — Albertine Rift endemic.

Elaphoglossum lancifolium (Desv.) C. V. Morton

First recorded — Pichi Sermolli (1985: 186) as Elapho glossum salicifolium (Willd. ex Kaulf.) Alston.

Elaphoglossum rwandense Pic. Serm.

First recorded — Pichi Sermolli (1985: 184).

Endemic status — Local endemic.

Elaphoglossum tanganjicense Kraijna ex Pic. Serm.

First recorded — Pichi Sermolli (1985: 186).

+Lastreopsis vogelii (Hook.) Tindale

New record — Rwanda: Northern Province: Kinigi, 25 Jun 1961, S. C. Antun Gupfert 1005 (BR0000017581714!).

Note — This specimen was deposited in BR as Lastreopsis sp. It has never been determined and published, and the species is not recorded for Rwanda in the checklist of Roux (2009). We searched for the species at Kinigi without success.

Gleicheniaceae

Dicranopteris linearis (N. L. Burm.) Underw.

First recorded — Pichi Sermolli (1983: 196).

Gleichenia elongata Baker

First recorded — Pichi Sermolli (1983: 196) as Gleicheniastrum elongatum (Baker) Nakai.

Sticherus flagellaris subsp. tomentosus (Reimers) Verdc.

First recorded — Pichi Sermolli (1983: 197) as Sticherus inflexus Pic. Serm.

Note — Roux (2009: 50) listed both taxa for Rwanda. However, Sticherus inflexus is generally considered to be a synonym of S. flagellaris subsp. tomentosus.

Hymenophyllaceae

Trichomanoideae

Abrodictyum rigidum (Sw.) Ebihara & Dubuisson

First recorded — Pichi Sermolli (1983: 252) as Selenodesmium rigidum (Sw.) Copel.

+Crepidomanes chevalieri (Christ.) Ebihara & Dubuisson

New record — Rwanda: Northern Province: Volcano NP, Ibuhanga Forest, terrestrial in submontane forest on lava rocks, 01°34′12.56″S, 29°38′08.17″E, 1625 m, 30 Mar 2009, E. Fischer s.n. (KOBL).

Note — Roux (2009) listed Crepidomanes chevalieri for Rwanda but without citing any source.

+Crepidomanes clarenceanum (F. Ballard) Pic. Serm.

New record — Rwanda: Western Province: Nyungwe NP, Cyamudongo Forest, epiphyte on mossy trees, often forming dense carpets, 02°33′04.03″S, 28°59′48.58″E, 1732 m, 6 Jan 2019, E. Fischer s.n. (KOBL).

Crepidomanes frappieri (Cordem.) J. P. Roux

First recorded — Pichi Sermolli (1983: 251) as Vandenboschia ramitricha (Faden) Pic. Serm.

Crepidomanes inopinatum (Pic. Serm.) J. P. Roux

First recorded — Pichi Sermolli (1983: 245) as Vandenboschia inopinata Pic. Serm.

Crepidomanes mannii (Hook.) J. P. Roux

First recorded — Pichi Sermolli (1983: 245) as Gonocormus mannii (Hook.) Copel.

Crepidomanes melanotrichum (Schltdl.) J. P. Roux

First recorded — Pichi Sermolli (1983: 249) as Vandenboschia melanotricha (Schltdl.) Pic. Serm.

Didymoglossum erosum (Willd.) J. P. Roux

First recorded — Pichi Sermolli (1983: 254) as Microgonium erosum (Willd.) C. Presl.

Polyphlebium borbonicum (Bosch) Ebihara & Dubuisson

First recorded — Pichi Sermolli (1983: 245) as Vandenboschia borbonica (Bosch) G. Kunkel.

Vandenboschia gigantea (Bory ex Willd.) Pic. Serm.

First recorded — Pichi Sermolli (1983: 250) as Vandenboschia radicans auct. non (Sw.) Copel.

Hymenophylloideae

Hymenophyllum capillare Desv.

First recorded — Pichi Sermolli (1983: 243) as Sphaerocionium capillare (Desv.) Copel.

Hymenophyllum kuhnii C. Chr.

First recorded — Pichi Sermolli (1983: 242) as Mecodium kuhnii (C. Chr.) Copel.

Hymenophyllum peltatum (Poir.) Desv.

First recorded — Pichi Sermolli (1983: 244).

Hymenophyllum splendidum Bosch

First recorded — Pichi Sermolli (1983: 243) as Sphaerocionium splendidum (Bosch) Copel.

Hymenophyllum triangulare Baker

First recorded — Pichi Sermolli (1983: 244) as Meringium triangulare (Baker) Copel.

Lindsaeaceae

Odontosoria africana F. Ballard

First recorded — Brause & Hieronymus (1910: 6) as Odontosoria melleri auct. non (Hook.) C. Chr.

Endemic status — Albertine Rift endemic.

Lomariopsidaceae

Lomariopsis warneckei (Hieron.) Alston

First recorded — Pichi Sermolli (1985: 180).

Marsileaceae

Marsilea gibba A. Br.

First recorded — Pichi Sermolli (1983: 241).

+Marsilea minuta L. var. minuta

New record — Rwanda: Eastern Province: Bugesera, Nyamata, seasonal shallow ponds on ferricretes, 02°07′00.91″S, 30°04′07.67″E, 1415 m, 9 Jan 2012, E. Fischer s.n. (KOBL); Mpanga, seasonal shallow ponds on ferricretes, 02°04′56.65″S, 30°46′39.96″E, 1310 m, Oct 1985, E. Fischer; Akagera NP, near Lake Ihema, 1 Oct 2013, E. Fischer s.n. (KOBL).

Note — Pichi Sermolli (1983) cited a specimen of Marsilea sp. cf. M. minuta L. from eastern Rwanda (piste Gabiro-Gatsibu, km 7, marais Kibondu, env. 1500 m, Van der Veken 10691 [BR0000017596121!]). The specimen is sterile and unidentifiable. There are four additional sterile specimens at BR.

Roux (2009: 56) listed Rwanda under Marsilea minuta, but did not mention a published record. Therefore, our collections from Rwanda represent the first definite record of the species.

Nephrolepidaceae

Nephrolepis undulata (Afz. ex Sw.) J. Sm.

First recorded — Brause & Hieronymus (1910: 6) as Nephrolepis cordifolia auct. non (L.) C. Presl.

Oleandraceae

Oleandra distenta Kunze

First recorded — Pichi Sermolli (1985: 189).

Osmundaceae

Osmunda hilsenbergii Grev. & Hook.

First recorded — Brause (1910: 37) as Osmunda regalis var. brevifolia Desv. and O. regalis var. capensis (Presl.) Milde.

Polypodiaceae

Crypsinoideae

Drynaria volkensii Hieron.

First recorded — Brause & Hieronymus (1910: 33).

Note — Some authors prefer the name Aglaomorpha volkensii (Hieron.) Hovenkamp & S. Linds. for this taxon, but we follow Wei & Zhang (2022).

Grammitidoideae

+Cochlidium serrulatum (SW.) L. E. Bishop

New record — Rwanda: Western Province: Nyungwe NP, Karamba, on moss cushions on wet rocks in montane forest, 1997 m, 02°29′10.98″S, 29°06′13.27″E, 20 Mar 2011, E. Fischer s.n. (KOBL).

Lellingeria oosora (Baker) A. R. Sm. & R. C. Moran

First recorded — Pichi Sermolli (1983: 199) as Xiphopteris oosora (Baker) Alston.

Melpomene flabelliformis (Poir.) A. R. Sm. & R. C. Moran

First recorded — Pichi Sermolli (1983: 197) as Ctenopteris rigescens (Bory ex Willd.) J. Sm.

Zygophlebia villosissima (Hook.) L. E. Bishop

First recorded — Pichi Sermolli (1983: 198) as Ctenopteris villosissima (Hook.) W. J. Harley

Loxogrammoideae

Loxogramme abyssinica (Baker) M. G. Price

First recorded — Brause & Hieronymus (1910: 33) as Polypodium loxogramma Mett.

Microsoroideae

Lepisorus excavatus (Bory ex Willd.) Ching

First recorded — Pichi Sermolli (1983: 200, 205) as Pleopeltis bambsii Pic. Serm., P. mildbraedii (Hieron.) Pic. Serm., P. rotunda (Bonap.) Tard.

Lepisorus schraderi (Mett.) Ching

First recorded — Pichi Sermolli (1983: 206) as Pleopeltis schraderi (Mett.) Tard.

+Microsorum scolopendria (Burm. f.) Copel.

New record — Rwanda: Western Province: Rubavu (= Gisenyi), epiphyte on roadside trees, 01°42′11.62″S, 29°15′32.15″E, 1472 m, 21 Sep 2021, E. Fischer s.n. (KOBL); Karongi, lithophyte on rocks, 1489 m, 02°03′46.81″S, 29°20′27.99″E, 21 Sep 2021, E. Fischer s.n. (KOBL); Mashyoza, on volcanic rocks, 1179 m, 02°35′00.06″S, 29°00′59.23″E, 25 Sep 2011, E. Fischer s.n. (KOBL).

Platyceridoideae

Pyrrosia schimperiana (Mett.) Alston

First recorded — Pichi Sermolli (1983: 206) as Pyrrosia mechowii (Brause & Hieron.) Alston

Note — Some authors prefer Hovenkampia schimperiana (Mett.) Li Bing Zhang & X. M. Zhou as correct name for this taxon. We follow Wei & Zhang (2022).

Platycerium elephantotis Schweinf.

First recorded — Pichi Sermolli (1983: 206).

Polypodoideae

+Pleopeltis macrocarpa var. dichotoma Hieron. ex Eb.

Fisch. & Lobin, var. nov. (see Taxonomic treatment)

New record — Rwanda: Volcano National Park, Mt Gahinga, on bamboo, 2900 m, 20 Mar 2022, E. Fischer, P. Ballings & B. Wursten s.n. (KOBL).

Pleopeltis macrocarpa (Bory ex Willd.) Kaulf. var. macrocarpa

First recorded — Brause & Hieronymus (1910: 33) as Lepicystis lanceolata (L.) Diels.

Pleopeltis macrocarpa var. pinnatiloba Hieron. ex Eb.

Fisch. & Lobin, var. nov. (see Taxonomic treatment)

First recorded — Brause & Hieronymus (1910: 33) as Lepicystis lanceolata var. pinnatilobata Hieron. nom. nud.

Pteridaceae

Cheilanthoideae

Aleuritopteris farinosa (Forssk.) Fée

First recorded — Brause & Hieronymus (1910: 29) as Cheilanthes farinosa (Forssk.) Kaulf.

Cheilanthes inaequalis (Kunze) Mett.

First recorded — Brause & Hieronymus (1910: 29) as Notholaena inaequalis Kunze.

Doryopteris concolor (Langsd. & Fisch.) Kuhn

First recorded — Brause & Hieronymus (1910: 28) as Doriopteris [sic!] concolor.

Pellaea calomelanos (Sw.) Link

First recorded — Brause & Hieronymus (1910: 28) as Pellaea hastata (L. f.) Link.

Pellaea doniana J. Sm. ex Hook.

First recorded — Kornaś & Nowak (1991: 12).

Pellaea involuta (Sw.) Baker

First recorded — Pichi Sermolli (1983: 216) as Pallea [sic!] involuta.

Pellaea pectiniformis Baker

First recorded — Kornaś & Nowak (1991: 12).

Pellaea quadripinnata (Forssk.) Prantl

First recorded — Brause & Hieronymus (1910: 28).

Pellaea schweinfurthii (Hieron.) Hieron.

First recorded — Kornaś & Nowak (1991: 13).

Pellaea viridis (Forssk.) Prantl

First recorded — Brause & Hieronymus (1910: 28).

Cryptogrammoideae

Coniogramme africana Hieron.

First recorded — Pichi Sermolli (1983: 236).

Pteridoideae

+Actiniopteris radiata (Sw.) Link

Newrecord—Rwanda: Eastern Province: Nyarubuye, quartzitic rocks, 02°08′48.69″S, 30°45′10.21″E, 1632 m, 12 Mar 2007, E. Fischer s.n. (KOBL).

Actiniopteris semiflabellata Pic. Serm.

First recorded — Pichi Sermolli (1985: 199).

+Anogramma leptophylla (L.) Link

New record — Rwanda: Northern Province: Volcano NP, foot of Mt Bisoke, 01°27′22.65″S, 29°30′21.67″E, 2717 m, 30 Sep 2009, E. Fischer s.n. (KOBL); Volcano NP, Muhabura, humid volcanic rocks, 01°22′02.11″S, 29°41′36.03″E, 2893 m, 17 Mar 2010, E. Fischer s.n. (KOBL).

Pityrogramma aurantiaca (Hieron.) C. Chr.

First recorded — Pichi Sermolli (1983: 236).

Pityrogramma calomelanos (L.) Link

First recorded — Kornaś & Nowak (1991: 13).

Pityrogramma elongata (C. Chr.) Pic. Serm.

First recorded — Pichi Sermolli (1983: 237).

Endemic status — Albertine Rift endemic.

Pityrogramma rupicola Pic. Serm.

First recorded — Pichi Sermolli (1983: 238).

Endemic status — Albertine Rift endemic.

Pteris auquieri Pic. Serm.

First recorded — Pichi Sermolli (1983: 219).

Endemic status — Albertine Rift endemic.

Pteris catoptera Kunze

First recorded — Brause & Hieronymus (1910: 30) as Pteris quadriaurita auct. non Retz.

Pteris cretica L.

First recorded — Brause & Hieronymus (1910: 30).

Pteris dentata Forssk.

First recorded — Pichi Sermolli (1983: 226).

Pteris intricata C. H. Wright

First recorded — Pichi Sermolli (1983: 227).

Pteris kivuensis C. Chr.

First recorded — Pichi Sermolli (1983: 227).

Endemic status — Albertine Rift endemic.

Pteris linearis Poir.

First recorded — Kornaś & Nowak (1991: 13).

Pteris microlepis Pic. Serm.

First recorded — Pichi Sermolli (1983: 227).

Pteris preussii Hieron.

First recorded — Pichi Sermolli (1983: 231).

Pteris pteridioides (Hook.) F. Ballard

First recorded — Pichi Sermolli (1983: 233).

Pteris vittata L.

First recorded — Brause & Hieronymus (1910: 30) as Pteris longifolia L.

Table 2.

Endemic and near-endemic clubmosses, quillworts and ferns of Rwanda. – Status: ARE = Albertine Rift endemic; LE = local endemic.

Vittarioideae

Adiantum capillus-veneris L.

First recorded — Kornaś & Nowak (1991: 9).

Adiantum incisum Forssk.

First recorded — Pichi Sermolli (1983: 234).

Adiantum poiretii Wikstr.

First recorded — Pichi Sermolli (1983: 236) as Adiantum thalictroides Willd. ex Schltdl.

Antrophyum mannianum Hook.

First recorded — Pichi Sermolli (1983: 241).

Haplopteris guineensis (Desv.) E. H. Crane

First recorded — Pichi Sermolli (1983: 239) as Vittaria guineensis var. orientalis Hieron.

Haplopteris reekmansii (Pic. Serm.) C. W. Chen & S. Linds.

First recorded — Pichi Sermolli (1983: 239) as Vittaria reekmansii Pic. Serm.

Endemic status — Albertine Rift endemic.

Salviniaceae

+Azolla nilotica Decne ex Mett.

New record — Rwanda: Western Province: Bugarama, in rice fields, 02°37′56.24″S, 29°01′00.88″E, 1040 m, 28 Sep 2009, E. Fischer s.n. (KOBL). Northern Province: Lake Bulera E of Butaro, 01°23′13.48″S, 29°47′49.09″E, 1864 m, 4 Dec 2021, E. Fischer s.n. (KOBL). Eastern Province: Lake Mugesera N of Karembo, Gisaya swamp, 02°03′40.44″S, 30°27′17.54″E, 1339 m, 8 Sep 2021, E. Fischer s.n. (KOBL); Rwinkwavu, floating on the water surface in swamps, 01°57′47.20″S, 30°55′23.33″E, 1360 m, 17 Sep 2009, E. Fischer s.n. (KOBL).

Azolla pinnata subsp. africana (Desv.) R. M. K. Saunders & K. Fowler

First recorded — Pichi Sermolli (1985: 192) as Azolla africana Desv.

Tectariaceae

Arthropteris anniana Lawalrée

First recorded — Pichi Sermolli (1985: 188) als Arthropteris monocarpa auct. non (Cordem.) C. Chr.

Arthropteris orientalis (Gmel.) Posth.

First recorded — Pichi Sermolli (1985: 189).

Tectaria fernandensis (Baker) C. Chr.

First recorded — Pichi Sermolli (1985: 178).

Tectaria gemmifera (Fée) Alston

First recorded — Pichi Sermolli (1985: 178).

Thelypteridaceae

Phegopteridoideae

Macrothelypteris rammelooi Pic. Serm.

First recorded — Pichi Sermolli (1983: 270).

Endemic status — Local endemic.

Thelypteridoideae

Amauropelta bergiana (Schlecht.) Holttum

First recorded — Pichi Sermolli (1983: 275).

Amauropelta oppositiformis (C. Chr.) Holttum

First recorded — Pichi Sermolli (1983: 276).

+Ampelopteris prolifera (Retz.) Copel.

New record — Rwanda: Western Province: Nyungwe NP, Cyamudongo Forest, terrestrial, mostly along small streams, occasionally epiphytic in montane forest, 02°32′26.89″S, 28°59′20.46″E, 1941 m, 1 Apr 2021, E. Fischer s.n. (KOBL).

+×Chrismatopteris holttumii Quansah & D. S. Edwards

New record — Rwanda: Western Province: Nyungwe NP, Pindura-Bweyeye, swamp in montane forest, 02°30′22.08″S, 29°13′59.40″E, 1960 m, 31 Mar 2021, E. Fischer s.n. (KOBL).

Note — This taxon is a generic hybrid between Christella dentata × Pneumatopteris afra. Both parents occur in Rwanda.

+Christella burundensis Pic. Serm.

New record — Rwanda: Western Province: Nyungwe NP, Cyamudongo Forest, forest floor in montane forest, 02°33′21.65″S, 28°59′09.12″E, 1889 m, 5 Jan 2019, E. Fischer s.n. (KOBL).

Endemic status — Albertine Rift endemic.

Christella dentata (Forssk.) Brownsey & Jermy

First recorded — Brause & Hieronymus (1910: 3) as Dryopteris mollis (SW.) Hieron.

Christella gueintziana (Mett.) Holttum

First recorded — Pichi Sermolli (1983: 280).

+Christella hispidula (Decn.) Holttum

New record — Rwanda: Western Province: Nyungwe NP, Cyamudongo Forest, terrestrial in montane rainforest, 02°32′29.33″S, 28°59′06.56″E, 2003 m, 2 Apr 2021, E. Fischer s.n. (KOBL).

Christella parasitica (L.) Lév.

First recorded — Kornaś & Nowak (1991: 11).

Cyclosorus interruptus (Willd.) H. Ito

First recorded — Brause & Hieronymus (1910: 3) as Dryopteris (Cyclosorus) striata (Schumach.) C. Chr.

Note — Verdcourt (2006) found it impossible to distinguish between three species [Cyclosorus interruptus, C. striatus (Schumach.) Ching, C. tottus (Thunb.) Pic. Serm.] that share the same ecology. We follow his opinion.

Leptogramma totta (Schltdl.) J. Sm.

First recorded — Pichi Sermolli (1983: 284) as Leptogramma pozoi non (Lag.) K. Iwatsuki.

Note — We follow Kuo & al. (2019), who separated this species from Leptogramma pozoi.

Table 3.

Collectors and authors and their contributions to clubmosses, quillworts and ferns of Rwanda (species number and new species).

+Menisorus pauciflorus (Hook.) Alston

New record — Rwanda: Western Province: Nyungwe NP, Gisakura, terrestrial fern, on deeply shaded rocks along streams in rainforest, 02°27′09.67″S, 29°07′04.06″E, 1835 m, 3 Apr 2021, E. Fischer s.n. (KOBL); Nyungwe NP, Cyamudongo Forest, 02°33′14.63″S, 28°59′03.28″E, 1870 m, 4 Apr 2021, E. Fischer s.n. (KOBL).

Metathelypteris vandervekenii Pic. Serm.

First recorded — Pichi Sermolli (1983: 272).

Endemic status — Local endemic.

+Pneumatopteris afra (Christ) Holttum

New record — Rwanda: Western Province: Nyungwe NP, Cyamudongo Forest, terrestrial in montane forest along streams, 02°33′14.63″S, 28°59′03.28″E, 1870 m, 20 Mar 2021, E. Fischer s.n. (KOBL).

Pneumatopteris unita (Kunze) Holttum

First recorded — Pichi Sermolli (1983: 283).

Pseudocyclosorus pulcher (Bory ex Willd.) Holttum

First recorded — Pichi Sermolli (1983: 277).

Thelypteris confluens (Thunb.) Morton

First recorded — Pichi Sermolli (1983: 275).

Taxonomic treatment

Hieronymus in Brause & Hieronymus (1910) separated Mildbraed's plants into three different taxa: Lepicystis lanceolata (= Pleopeltis macrocarpa var. macrocarpa), L. lanceolata var. pinnatiloba Hieron. nom. nud., and L. lanceolata var. dichotoma Hieron nom. nud. All material cited by him is deposited in B and has been examined by us. Unfortunately, Hieronymus in Brause & Hieronymus (1910) gave no descriptions and therefore published nomina nuda, but as he placed his name behind the varieties, he certainly regarded them as new to science. We therefore decided to validate them (see below).

In his treatment of Polypodiaceae for the Flora of Tropical East Africa, Verdcourt (2001: 28) assigns a “mutation” to some collections from Uganda and Kenya, citing Schelpe & Anthony (1986) who discussed these forms. In South Africa, Pleopeltis ×simiana (Schelpe & N. C. Anthony) N. R. Crouch & Klopper is considered to be a natural hybrid between P. macrocarpa and P. polypodioides subsp. ecklonii (Kunze) J. P. Roux. This hybrid looks quite similar to the East African plants and to our material from Rwanda. Verdcourt (2001) already points out that these specimens occur far from the natural range of P. polypodioides subsp. ecklonii (SE Tanzania, Mozambique, Malawi, S Africa) and the plants from Rwanda have, as do the three examined specimens in Flora of Tropical East Africa, normal rather than abortive spores (Verdcourt 2001). Therefore, we propose, that these specimens merit recognition as separate taxa.

Similar forms with pinnatilobed fronds have been recently described as new species from eastern D. R. Congo. Loxogramme ntahobavakiana Mangambu Mokoso & van Diggelen (2017: 64) differs from L. abyssinica mainly in the pinnatilobed leaves. Lepisorus robbrechtianus Mangambu Mokoso & van Diggelen (2017: 65) is separated from L. schraderi mainly by the presence of long and dichotomously lobed leaves. However, we prefer to keep the material from Pleopeltis macrocarpa forms from eastern D. R. Congo and Rwanda in the rank of varieties.

Pleopeltis macrocarpa var. dichotoma Hieron. ex Eb. Fisch. & Lobin, var. nov. – Fig. 3.

Holotype: D. R. Congo, Ninagongo (= Nyiragongo), 2000–2500 m, 3 Oct 1907, J. Mildbraed 1316a (B 20 0025283 [https://herbarium.bgbm.org/object/B200025283]).

– Lepicystis lanceolata var. dichotoma Hieron., nom nud. in Brause & Hieronymus (1910: 33).

Diagnosis — The new variety differs from typical P. macrocarpa var. macrocarpa in the lamina dichotomously divided at the top, bifurcate, with each lobe also being bifurcate.

Distribution — Known only from the Virunga Volcanoes in D. R. Congo and Rwanda.

Habitat — Epiphyte in montane forest, 2000–2900 m.

Additional specimens seen (paratypes) — D. R. Congo: Ninagongo (= Nyiragongo), Acanthus-Busch und unterer Waldgürtel, 2000–2500 m, 3 Oct 1907, J. Mildbraed 1316, junge Pflanze [young plant on lower right of the sheet], together with L. lanceolata var. pinnatiloba Hieron. [upper left of the sheet] (B 20 0025281); Kihawe (P. Karisimbi), 2400 m, 7 Mar 1935, De Witte 2295 (BR0000019902777) (together with var. pinnatiloba). — Rwanda: Volcano National Park, Mt Gahinga, on bamboo, 2900 m, 20 Mar 2022, E. Fischer, P. Ballings & B. Wursten s.n. (KOBL).

Pleopeltis macrocarpa var. pinnatiloba Hieron. ex Eb. Fisch. & Lobin, var. nov. – Fig. 4.

Holotype: Rwanda, Station Kissenye (= Gisenyi, Rubavu), Bugoie (= Gishwati forest), 2300 m, 1 Nov 1907, J. Mildbraed 1446 (B 20 0025282 [https://herbarium.bgbm.org/object/B200025282]).

– Lepicystis lanceolata var. pinnatilobata Hieron. nom nud. in Brause & Hieronymus (1910: 33).

Diagnosis — The new variety differs from typical Pleopeltis macrocarpa (Willd.) Kaulf. var. macrocarpa in the pinnatilobed fronds with long and narrow pinnae. From the hybrid P. ×simiana (Schelpe & N. C. Anthony) N. R. Crouch & Klopper, with which it shares the pinnatilobed fronds, it is distinguished by fertile spores, while the latter only has abortive spores. Finally, one parent from the hybrid, P. polypodioides subsp. ecklonii (Kunze) J. P. Roux, does not occur in Rwanda.

Distribution — D. R. Congo (Virunga Volcanoes, Ruwenzori), Rwanda (Virunga Volcanoes, Gishwati) and Uganda (Muhabura); also reported from Kenya (not seen).

Habitat — In Rwanda, the new variety occurs in almost pure populations, not in mixed stands together with the typical variety. They have been observed in the montane forest belt up to the bamboo belt of the Virunga Volcanoes between 2500–3027 m.

Note — Plants of both varieties are in cultivation in the Bonn University Botanical Gardens: Pleopeltis macrocarpa var. dichotoma (BG Bonn No. 47370) and P. macrocarpa var. pinnatiloba (BG Bonn No. 47369). In cultivation both taxa kept their typical leaf form (pinnatilobed and dichotomously branched respectively) (Fig. 3, 4) even in the newly produced leaves. This is a strong argument for a genetic fixation and against an ecoform induced by the habitat conditions.

Additional specimens seen (paratypes) — D. R. Congo: Ninagongo (= Nyiragongo), Acanthus-Busch und unter-er Waldgürtel, 2000–2500 m, 3 Oct 1907, J. Mildbraed 1316, [upper left of the sheet, together with P. macrocarpa var. dichotoma] (B200025281); Kihawe (Karisimbi), 2400 m, 7 Mar 1935, De Witte 2295 (BR0000019902777) (together with P. macrocarpa var. dichotoma); Parque National Albert, volcan Karisimbi, flanc E, 2600 m, 21 Aug 1937, J. Louis 5441 (BR0000019902821); Nyamlagira, 2000 m, 22 Dec 1944, R. Germain 3138 (BR0000019902784); Ninagongo, 2200 m, H. Humbert 7934 (BR0000019902791); entre Kimbundo et le premier crète de Mikeno, 2175 m, Aug 1937, J. Lebrun 718; Kivu, Lusengi, 1500 m, May 1958, AntunGupffert 173 (BR0000019902722); Ruwenzori, Lanuri, 2000 m, 15 Apr 1914, Bequaert 4244 (BR0000019902739). — Rwanda: Northern Province: Volcano National Park, Sabinyo, epiphyte in montane forest, 2577 m, 01°24′37.13″S, 29°36′13.51″E, 4 Jan 2017, E. Fischer s.n. (KOBL); Gahinga, epiphyte in montane forest, 3027 m, 01°23′23.72″S, 29°39′27.84″E, 23 Sep 2006, E. Fischer s.n. (KOBL); Mt Gahinga, on bamboo, 2900 m, 20 Mar 2022, E. Fischer, P. Ballings & B. Wursten s.n. (KOBL).

Author contributions

Both authors contributed equally to the manuscript. Fieldwork was carried out by Eberhard Fischer.