Diplazium humbertii (C.Chr.) Pichi Sermolli (1973: 444)

Fischer, Eberhard & Lobin, Wolfram, 2023, Synoptic Revision of Diplazium (Athyriaceae) in Rwanda with description of Diplazium cyamudongoense sp. nov., Phytotaxa 600 (3), pp. 169-183 : 175

Diplazium humbertii (C.Chr.) Pichi Sermolli (1973: 444) ( Figs. 4 E–F , 6–7 ).

Athyrium humbertii Christensen (1937: 54)

Lectotype (designated by Pichi Sermolli 1973):— D.R. CONGO. North Kivu: Montagnes à l’Ouest du Lac Kivu (Congo Belge). Forêt, 2000–2400 m, February–March 1929, H. Humbert 7497 ( BM000918405! ; isolectotype BM000918404! )

Specimens seen: — RWANDA. Western Province: Nyungwe National Park, route Astrida (= Huye) – Bukavu, vers km 93, forêt de Rugege (= Nyungwe) près d’Uwinka, Territ. Shangugu (= Rusizi), 24 September 1956, G. Troupin 2598 (BR0000013688578); a sud-est del lago Kivu a 45 km da Bukavu lungo la strada per Astrida (= Huye), 15 August 1956, R. Pichi Sermolli 5323 (BR0000013688585); Forêt de Nyungwe, environs de Kamiranzovu, Préfecture Cyangugu (= Rusizi), September 1971, G. Bouxin 1211 (BR0000013688462); Kamiranzovu, 11 August 2007, E. Fischer s.n. (KOBL); Cyamudongo Forest, 4 April 2021, E. Fischer s.n. (KOBL).

Distribution in Rwanda: —Western Province, Nyungwe National Park.

Distribution in Africa: Eastern D.R. Congo, Western Uganda, Western Rwanda, Western Burundi, Western Tanzania. Albertine Rift endemic.

Habitat: —Montane rainforest, elev. 1900–2400 m.

Note: —The spores ( Fig. 4 E, F ) resemble those of Diplazium cyamudongoense sp. nov. (Fig, 4 A–D) and have a cristate perispore, 54.3–57.2 × 28.6–37.1 µm, the alae are 5.7–7.15 µm high and 1.5–2.86 µm wide. The remaining perispore bears up to 1.4–1.6 µm long spine-like scattered projections.

Figures

FIGURE 4. Diplazium cyamudongoense Eb.Fisch. & Lobin sp. nov.—A–D. Spores.— Diplazium humbertii —E–F. Spores. Photographs: E.Fischer, W.Lobin & Y.Malkowsky, A–D. Cyamudongo; E–F. Cyamudongo. Scale bars: A, B, C, E, F. 10 µm; D. 8 µm.

FIGURE 6. Diplazium humbertii.—A. Frond.—B. Frond with young plant at apex developing from gemma.—C. Detail of stipe with scales.—D. Pinnules showing sori. Photographs: E.Fischer, A, C–D. Pindura-Bweyeye; B. Cyamudongo. Scale bars; A, B. 5 cm; C. 1 cm; D. 5 mm.

FIGURE 7. Diplazium humbertii.—A. Frond.—B. Frond with young plant at apex developing from gemma.—C. Gemma at apex.—D. Rachis with base of pinnules.—E. Pinnules showing sori. Photographs: E.Fischer, Cyamudongo. Scale bars: A.10 cm; B, C, D.1 cm; E. 5 mm.