Pleopeltis macrocarpa var. pinnatiloba Hieron. ex Eb. Fisch. & Lobin, 2024

Fischer, Eberhard & Lobin, Wolfram, 2024, Checklist of Lycopodiopsida (clubmosses and quillworts) and Polypodiopsida (ferns) of Rwanda, Willdenowia 53 (3), pp. 149-172 : 168-169

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, Antun-Gupffert 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).