Isoglossa humbertii Mildbraed (1937: 358)

Champluvier, Dominique & Fischer, Eberhard, 2020, Isoglossa darbyshirei (Acanthaceae), a new plietesial species from the Albertine Rift (Rwanda, Burundi), Phytotaxa 438 (5), pp. 276-288 : 285

Isoglossa humbertii Mildbraed (1937: 358) ( Figs. 5 – 6 )

Type: — DEMOCRATIC REPUBLIC OF THE CONGO. Montagnes à l’Ouest du Lac Kivu, entre Tshibinda et le marais Kanzibi, (au SE du marais, 2000–2400 m, February–March1929, Humbert 7445 (holotype B †; isotype BR0000006273507 !, P!).

Specimens examined:— DEMOCRATIC REPUBLIC OF THE CONGO. Lacs Edouard et Kivu. Kivu, Kalehe, km 25 route Kavumu – Walikale , Mt. Kahuzi, 2600 m, 1 July 1955, Christiaensen 947 ( BR) ; Kivu, Kalehe, 27 November 1955, Deuse 55/9 ( BR) ; Distrikt Kivu-Sud, Kahuzisattel, an der Strasse Bukavu – Walikale, 2600 m, 23 January 1955, Stauffer 1121 ( BR) ; Mt. Bukulumiza , Mulungu, Kivu-Sud, 2300 m, 13 December 1956, Pierlot 1421 ( BR) ; Bukumuliza, Mulungu, Kabare, 2400 m, 8 October 1958, Gutzwiller 3679 ( BR) ; Kamatale, Gungu, Masisi, 2380 m, 30 June 1958, Gutzwiller 1910 ( BR) . UGANDA. U3, Toro District , Ruwenzori, Butahu valley, July 1932, Humphreys 1362 ( K) .

Note:— A specimen from Ruwenzori (Ross 918, Nyamagasani Valley, Musalombe Forest, K), with up to 6.5 cm wide leaves and crisped hairs (see Darbyshire et al. 2010) is here excluded until further studies are available.

Figures

FIGURE 5. Comparative leaf and floral images.A–C.Isoglossa laxiflora. A–B. Leaves.C. Flower, lateral view. D–E. Isoglossa humbertii. D. Leaf. E. Flower, lateral view. F–G. Isoglossa darbyshirei. F. Leaf. G. Corolla, lateral view. All drawn by E. Fischer from Dumbo s.n. (A), Fischer 462/11 (B–C), Stauffer 1121 (D–E) and Fischer 788/16 (F–G).