Microstachys glandulosa (Mart. & Zucc.) Esser & M.J.Silva

Silva, Marcos José Da & Esser, Hans-Joachim, 2011, Two new taxa and two new combinations in Microstachys (Euphorbiaceae) from South America, Phytotaxa 32, pp. 18-26 : 19-20

Microstachys glandulosa (Mart. & Zucc.) Esser & M.J.Silva , comb. et stat. nov.

Basionym:— Cnemidostachys glandulosa Martius & Zuccarini (1824: 139) ; Martius (1824: 71). — Sebastiania corniculata var. obtusifolia forma glandulosa (Mart. & Zucc.) Müller (1866: 1168) .— Sebastiania glandulosa (Mart. & Zucc.) Pax in Pax & Hoffmann (1912: 100).— Sebastiania glandulosa var. obtusifolia forma calvescens Pax in Pax & Hoffmann (1912: 101), nom. inval.

Lectotype (designated here): BRAZIL. Minas Gerais: in campis, without date, C. F. P. von Martius s.n. (M-0164455!, isolectotypes M- 0164454!, M-0164456!).

Cnemidostachys glandulosa had been overlooked by Esser (1998), and was later listed as synonym of M. corniculata (Vahl) Griseb. by Govaerts et al. (2000: 1186), which was certainly erroneous. It is a separate species, characterized by broadly elliptic to suborbicular, pubescent leaves with an obtuse to rounded (never cordate) base, an obtuse to subacute apex and several distinct marginal glands on the lower surface, which are situated in small lateral lobes that give the leaves a slightly dentate appearance (hence the appropriate epitheton).

The species is very similar to M. hispida ; the latter species shows, however, elliptic-lanceolate leaves with usually acute to acuminate apex, shoots and twigs are hollow or not in cross section, the fruits are regularly tricarpellate, with conspicuous appendages often pointing upwards, the pubescence is velutinose in addition to hispid and never uncinate hairs, the growth of the plants is erect and never caespitose. M. glandulosa differs from it, in addition the leaf shape, by the stems never hollow, the fruits quite often showing one or two aborted carpels with only vestigial to reduced appendages, the trichomes hispid and often uncinate, and the plants are often caespitose.

Among the three type sheets in M, the only one with the original label of Martius is selected as lectotype (the others being duplicates with copied labels), which is also the only one with an annotation label of Müller Argoviensis attached to it. The leaves of the lectotype are slightly larger (30–35 × 13–15 mm) than those of the duplicates (15–25 × 8–12 mm) .