Boehmeria didymogyne Wedd.

Wilmot-Dear, C. M. & Friis, I., 2013, The Old World species of Boehmeria (Urticaceae, tribus Boehmerieae). A taxonomic revision, Blumea 58 (2), pp. 85-216 : 105-107

3. Boehmeria didymogyne Wedd. — Fig. 3 ; Map 5

Boehmeria didymogyne Wedd. (1869) 204. ― Type: Parish s.n. (holo K; iso NY), Burma, Moulmein , 1862.

Slender herb, up to 0.5 m tall; main stem leafless in lower part with few branches near apex, ultimate branches c. 0.8 mm diam, glabrous or with indumentum of scattered fine soft long hairs, soon becoming thick (possibly fleshy) and glabrous. Stipules narrowly triangular, thin-chartaceous, 4–5 by 1.2 mm, glabrous or with hairs abaxially like the stem. Leaves alternate, markedly dimorphic in size and somewhat in shape, with length of ‘larger’ leaves c. 3 × that of ‘smaller’; ‘larger’ leaves ovate but often slightly asymmetrical (outline of one half ovate, of other half elliptic), medium-sized, 7–10 by 4–5 cm, length c. 2 × width; margin entire in proximal third or half, crenate-dentate distally with (5–)10–15 teeth either side, these broad, conspicuous, 1.5–2.5 by 3–7 mm; leaf apex abruptly acuminate with single long tooth; base asymmetrically cuneate; basal veins running into margin beyond middle of lamina (on one side slightly further than other), upper lateral veins 1–2, arising near apex but hardly distinguishable from coarser reticulation, visible adaxially, fine-prominulous abaxially; texture membranous; surface smooth and glabrous adaxially or with occasional

d

long fine hairs, similar hairs present and less sparse abaxially, mostly restricted to veins; petiole very variable short or up to half of lamina length, 1.5–5 cm, glabrous or sparsely hairy like the leaf; ‘smaller’ leaves relatively broader, often acute at apex, often toothed nearer to base and usually with very short petiole. Flower­clusters axillary, lower ones male or bisexual, 2–4 mm diam, with c. 15–30 crowded flowers, upper ones female, of similar size or smaller with fewer flowers; bracteoles inconspicuous, up to 0.3 mm long, linear, oblong to obovate. Male flowers 3- (or 4-, according to Weddell)merous, subsessile, mature buds depressed-globose, c. 1 mm diam, tepals with prominent dorsal appendages and abundant conspicuous hooked hairs. Female perianth rather long, narrowly ovoid to ellipsoid, 1–1.2 by c. 0.6 mm, narrowing gradually or abruptly into markedly long beak up to 0.4 mm and up to c. half of flower length, apparently much-flattened (possibly feature of drying and/or pressing) with hairs abundant, fine, long, spreading; stigmas 1–2 (or stigma possibly bilobed), only 0.4–0.6 mm long. Mature achenes not seen.

Distribution ― Burma.

Habitat & Ecology ― Unknown, as there is no information on the specimens and the exact locality is not known with sufficient precision to obtain modern information. Since the known collections are from near-coastal localities and the habit is slender with membranous leaves, it is presumed that the species occurs in coastal rainforest or other shaded habitats.

Conservation status ― Data Deficient (DD). Known from only one locality (Moulmein) and two old collections (the type and 18 Oct. 1875, Kuntze 6274 (NY)). However, the area has undergone considerable conversion from natural habitats to farmland and the species is probably at risk.

Note ― This species appears to be unique in the Old World species of Boehmeria in its tendency to paired stigmas (suggesting paired fused fruiting perianths as seen otherwise only in the Central American endemic B. burgeriana (Wilmot-Dear et al. 2003) and apparently 3-merous male flowers. It is also distinctive in its axillary flower-clusters, slender habit and leaves which are alternate, membranous, glabrous or sparsely hairy adaxially, with conspicuous teeth only in distal part. It does not closely resemble any other species of Boehmeria .

Figures

Map 5 Distribution of Boehmeria didymogyne Wedd.(▲), B. helferi Blume (●) and B. manipurensis Friis & Wilmot-Dear (■).

Fig. 3 Boehmeria didymogyne Wedd. a. Habit; b. large leaf; c. leaf, detail of adaxial surface and margin; d. detail of abaxial surface; e. axillary male flowercluster (inflorescence); f. male flower; g. axillary female inflorescence; h. female perianth and single stigma; i. female perianth and paired stigmas (all: Parish 400; K). — Scale bars: a = 2 cm; b = 1 cm; c, d = 5 mm; e–i = 1 mm.