An updated checklist of vascular plants (lycophytes, ferns, gymnosperms, angiosperms) from Nyungwe National Park (incl. Cyamudongo Forest), Rwanda

An updated checklist of vascular plants of Nyungwe National Park, since September 2023 also a UNESCO-World heritage site, is provided. A short overview of the conservation history, the history of botanical exploration, and on vegetation and its altitudinal zonation is presented. For lycophytes and ferns, 145 species have been recorded. In the main forest block of Nyungwe 124 species are found, while 55 species occur in the isolated Cyamudongo Forest. In Rwanda, 21 species are restricted to Cyamudongo. The most species rich families are Aspleniaceae (34), Pteridaceae (17), Dryopteridaceae (15), Hymenophyllaceae (14), Thelypteridaceae (13), and Polypodiaceae (10). For flowering plants (gymnosperms and angiosperms), 1311 species in 137 families are recorded from Nyungwe National Park. The main forest block harbours 982 species, while 605 species occur in Cyamudongo, and 339 species are found in Rwanda only in Cyamudongo. The most species-rich family is Orchidaceae with 198 species recorded, followed by Asteraceae with 105, Rubiaceae with 89, Poaceae with 65, Fabaceae with 57, and Acanthaceae with 46. No less than 56 species of flowering plants are recorded here for the first time for Rwanda. For lycophytes and ferns, 24 species are Albertine Rift Endemics, at least present in Rwanda and Eastern D.R. Congo or Burundi, of which six species are Local Endemics, at present only known from Rwanda. The 24 endemic species represent 16.5% of the total fern flora of Nyungwe National Park. Four endemic species are restricted in Rwanda to Cyamudongo of which three have not been found elsewhere. For flowering plants, 234 species are endemics or near-endemics. These represent 17.7% of the flowering plants recorded in Nyungwe. Up to now, 33 species are only known from Rwanda (local endemics), while 200 species are Albertine Rift endemics. A total of 29 endemics are restricted in Rwanda to Cyamudongo Forest, among them 15 species are restricted to Cyamudongo on a world-wide scale. Within Nyungwe National Park 34 exotic and naturalised species have been recorded, among them the following invasive Neophytes expanding into natural vegetation and thus being a threat (Acacia mearnsii, Desmodium intortum, Solanum chrysotrichum, S. mauritianum). For several species, new combinations and new names are proposed: Impatiens kagamei Eb.Fisch. (Balsaminaceae), Dinophora montana (Troupin) Eb.Fisch. (Melastomataceae), Englerophytum rwandense (Troupin) Eb.Fisch. (Sapotaceae). For Culcasia scandens, Culcasia falcifolia (Araceae), Erica bequaertii, E. rugegensis and E. kingaensis (Ericaceae), and Medinilla afromontana (Melastomataceae), the distinguishing characters are provided. The synonymy of Ranunculus rugegensis and R. bequaertii (Ranunculaceae) is confirmed. A lectotype for Erica kingaensis is designated here. The differences between Nyungwe National Park and other protected areas in the Albertine Rift (Bwindi-Impenetrable NP, Kahuzi-Biega NP, Kibira NP) or outside (Mt. Elgon NP and Aberdare NP) are briefly discussed.