Euphorbia plagiantha Drake del Castillo (1903: 44)

Haevermans, Thomas & Hetterscheid, Wilbert L. A., 2022, Typification issues in Euphorbia section Plagianthae (Euphorbiaceae), Phytotaxa 547 (1), pp. 77-86 : 80

Euphorbia plagiantha Drake del Castillo (1903: 44)

( Figs. 1–3 , 6–9 ).

Type :— MADAGASCAR. Toliary: Anosy, “ Behara ”, [24°56′60″S 46°22′60″E], 18 October 1901, G. Grandidier s.n. (holotype P00078077 !) . Epitype (here designated):— MADAGASCAR. Toliary: Anosy , Amboasary-Sud , Behara , “ Canton Behara , District Amboasary ”, [24°56′60″S 46°22′60″E], 11 October 1958, Réserves Naturelles (coll. Rakotoson) 10062RN ( P05543011 ! , isoepitype: P00224820 !) .

— Euphorbia fiha Decary (1921: 21) . Lectotype (here designated):— MADAGASCAR. Toliary : Androy, “Tsihombe”, [25°18′0″S 45°28′60″E], s. dat. [specimen received at P on 4 December 1919], R. Decary s.n. (P00224809!) [reproduced here in Fig. 8 ].

Note:— The holotype of Euphorbia plagiantha is very poor and consists only of dried capsules. We decided here to designate an epitype based on a specimen collected from the type locality (Behara) to ascertain the application of the name. The name E. fiha Decary was first cited as synonym of E. plagiantha Drake del Castillo in Govaerts et al. (2000). Decary (1921: 21) did not cite specimens for his description, only a set of localities where the plant is reportedly found (“Tsihombe”, “Narahy”, “ North of Ankaboa ”, “Ankilitelo”). Of all the specimens available at P by R. Decary (Decary s.n., 3370, 3377, 3408, 3760, 4652, 10449, 10678), only one (Decary s.n.) predates 1921 (the year of publication of the name) and has been collected in Tsihombe and received at P in 1919. This specimen (reproduced in Fig. 8 ) bears an original field label “ Euphorbia fiha (décrit dans Bull. Ac. Malg.) Tsihombe”, likely by Decary himself and thus constitutes material he has seen. For this reason Decary s.n. has to be designated as a lectotype. Decary (1921: 21) mentions that his epithet is derived from plants known in the south of Madagascar under the local name “ Fiha ”, a term first mentioned by Poisson (1912: 126) for a yet to describe “Euphorbe” [French for spurge] matching Decary’s species.

Figures

FIGURE 1. Euphorbia plagiantha. A. branches with capsules; B. detail of the bark. Credits: T.Haevermans.

FIGURE 2. Euphorbia plagiantha. A. trunk with peeling bark; B. adult plant habit. Credits: P.E.Berry.

FIGURE 3. View of the habitat of Euphorbia plagiantha near Fort-Dauphin, in South-West Madagascar. Credit: P.E.Berry.

FIGURE 6. Holotype of Euphorbia plagiantha Drake, Grandidier s.n. (P00078077). Credit: Muséum national d’histoire naturelle, Paris.

FIGURE 7. Epitype of Euphorbia plagiantha Drake. Réserves Naturelles (coll. Rakotoson) 10062RN (P05543011). Credit: Muséum national d’histoire naturelle, Paris.

FIGURE 8. Lectotype of Euphorbia fiha Decary, Decary s.n. (P00224809). Credit: Muséum national d’histoire naturelle, Paris.

FIGURE 9. Distribution map of Euphorbia plagiantha (red) and Euphorbia salota (green), both endemic to Madagascar.