Microstachys stipulacea (Müll.Arg.) Esser & M.J.Silva 2011

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 : 24

Microstachys stipulacea (Müll.Arg.) Esser & M.J.Silva , comb. et stat. nov. (fig. 3)

Basionym:— Gymnanthes stipulacea Müller (1863: 96) .— Stillingia stipulacea (Müll.Arg.) Baillon (1865: 325) .— Sebastiania stipulacea (Müll.Arg.) Müller (1866: 1176) .

Lectotype (designated here): BRAZIL / URUGUAY: Without locality, without date, F. Sellow 3456 ( G!, isolectotypes G!, K!, P!).

Subshrub to ca. 30 cm tall. Completely glabrous. Leaves: stipules linear, 2–2.5 × ca. 0.4 mm, often persistent; petiole 10 mm long; blade broadly elliptic to suborbicular, 16 × 12 mm, base obtuse, margin shallowly crenate-serrate, apex rounded to subacute, slightly glaucous below, without marginal glands, side veins in 5–6 pairs. Staminate inflorescence 6–7 mm long; bracts c. 0.25 mm long, with a pair of stipitate disc-shaped glands ca. 0.15 mm in diam.; staminate flowers three per bract, their pedicel ca. 0.2 mm long, the calyx ca. 0.12 mm long. Pistillate flowers not seen. Fruits: pedicel ca. 1.3 mm long; capsule ellipsoid, sulcate, ca. 3.2 × 3.2 mm, smooth, with rows of multiple short appendages to ca. 0.7 mm long.

This species had been included by Pax & Hoffmann (1912) in their section Elachocroton (F. Müller 1857: 17) Pax & Hoffmann (1912: 114) , which is now part of Microstachys . Esser (1998) suggested that it might not belong to Microstachys because of some unusual characters. Study of the type showed, however, that it is a species which is unusual for its long petioles and stipules and for being completely glabrous, but has flowers and fruits typical for Microstachys .

Pax & Hofmann (1912) and Govaerts et al. (2000) listed the name ' Microstachys stipulacea (Müll.Arg.) Klotzsch ex Baillon' as a synonym under Sebastiania stipulacea . That name was however never validly published. The herbarium name of Microstachys stipulacea of Klotzsch (who died 1860) predates the publication of Müller (1863), but was only cited as synonym by Baillon (1865). Both Baillon and Müller treated the species under different genera and did not accept the original herbarium name of Klotzsch.

The original type collection (Sellow 3456, B) was labelled as being collected in ‘Brasil’, and as such, cited for Brazil by e.g., Pax & Hoffmann (1912). Urban (1893) showed, however, that Sellow’s collection numbers 3331–3623 were collected while travelling from southernmost Brazil into northern Uruguay and back to Alegrete. Therefore the type locality is uncertain. The holotype is lost. There are two type sheets in G. The lectotype chosen here is a poor specimen but with original annotations by Müller. The isolectotype is a better collection, but without original labels (fig. 3).

Additional specimens examined:— BRAZIL. ‘Prov. Rio Grande’, 1833 (fl, fr), C.Gaudichaud-Beaupré 1697 ( P!); URUGUAY. Without locality, 1816–1821 (fl, fr), A.Saint-Hilaire 2556 ( P!, two sheets).