Diplazium zanzibaricum (Baker) Christensen (1905: 241)

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 zanzibaricum (Baker) Christensen (1905: 241) ( Figs. 8–10 ).

Asplenium zanzibaricum Baker (1891: 311) . Deparia zanzibarica (Baker) Christenhusz (2018: 25) .

Holotype: — TANZANIA. Mainland westward of Zanzibar, March 1885, G.J. Last 261 (K000351065!).

Specimens seen: — RWANDA. Northern Province: Volcano National Park, foot of Bisoke, 2800 m, 22 September 2021, E.Fischer s.n. (KOBL); Sabinyo, ravin Rwebeya, 14 October 2009, E.Fischer s.n. (KOBL); Sabinyo, 2750 m, 14 January 2017, E.Fischer s.n. (KOBL); Gahinga, 2800 m, 20 March 2022, E.Fischer, P.Ballings & B.Wursten s.n. (KOBL).

Distribution in Rwanda: —Northern Province, Volcano National Park.

Distribution in Africa: —D.R. Congo, Rwanda, Uganda, Kenya, Tanzania, Zambia, Malawi, Mozambique, Zimbabwe, Rep. South Africa.

Habitat: —In Rwanda in montane forests with Dombeya , Hagenia -Hypericum Forest and bamboo forest from elev. 2750–3100 m, elsewhere in East Africa already at elev. 1450 m (fide Verdcourt 2003).

First recorded for Rwanda: — Kornaś & Nowak (1991) on Mt. Bisoke.

Note: —The species has been collected already by Mildbraed in 1907 in the Congolese part of the Volcanoes. The specimen Mildbraed 1324 (Ninagongo, oberer lichter Cornuswald, 2800 m ü. M., 4 October 1907, B 20 0028984!) bears a handwriting by Hieronymus ( Athyrium mildbraedii sp. nov.) and a description of the almost smooth spore (“Sporen ohne Kamm und anastomosierende Leisten” = spores without folds and anastomosing alae, pers. translation) ( Fig. 10 ). However, this new species was never published.

In Brause & Hieronymus (1910: 7) there is a note that this species belongs to Athyrium (“Geĥrt nicht unter Diplazium , sondern zu Athyrium ” = “doesn’t belong to Diplazium , but to Athyrium ”, pers. translation). Christenhusz (2018: 25) placed the taxon in the genus Deparia ( Hooker & Greville 1829: t. 154).

Diplazium zanzibaricum has an East African distribution, while the West African specimens belong to D. velaminosum ( Pichi Sermolli 1973) .

Figures

FIGURE 8. Diplazium zanzibaricum.—A. Habit.—B. Frond.—C. Pinnules showing sori. Photographs: E.Fischer, Karisoke. Scale bars: A, B. 20 cm, C. 1 cm.

FIGURE 9. Diplazium zanzibaricum.—A. Young shoot showing scales.— B. Detail of stipes with scales.—C. Pinnules showing sori. Photographs: E.Fischer, Gahinga. Scale bars: A. 5 cm; B, C. 1 cm.

FIGURE 10. Diplazium zanzibaricum. Spores.—A–D. Photographs: E.Fischer, W.Lobin & Y.Malkowsky, E.Fischer s.n., Gahinga. Scale bars:A. 20 µm; B, D. 10 µm; C 8 µm.