Boehmeria kurzii Hook.f.

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 : 129-131

15. Boehmeria kurzii Hook.f. — Fig. 13 ; Map 14

Boehmeria kurzii Hook.f. (1888) 577. ― Type: Kurz 3115 (holo K; iso CAL), Burma, Pegu.

Habit unknown; ultimate stems up to 1.3 mm diam, glabrescent or hairy, hairs very fine, short adpressed. Stipules very early deciduous, not seen. Leaves opposite, scarcely dimorphic with ‘larger’ up to 1.25 × length of ‘smaller’, narrowly ovate, 13.5–19 by 5–5.5 cm, length 3.5 × width; margin entire; leaf apex attenuate to indistinctly acuminate; base broadly cuneate; basal veins extending almost to apex, upper veins 0–1(–2), arising very near apex but scarcely distinguishable from coarser tertiary venation, coarser tertiary venation conspicuously scalariform, close-spaced, 2–4 mm apart, finer tertiary venation reticulate, all veins finely prominent abaxially; texture membranous; glabrous both sides or hairy on main veins, hairs very sparse adpressed; adaxial surface with abundant cystoliths giving slightly rough feel; petiole c. 2.5 cm long, 0.13 × lamina length. Flower­clusters borne on leafless inflorescence-bearing axes, these apparently always bisexual, unbranched, up to 20 cm long, 1 per axil; male clusters in lower part of axil, female above, a few clusters with both sexes; bracts very conspicuous, broadly triangular-cordate, c. 1.4 by 1.6 mm, with broad apex sharply acute at extreme tip; clusters spaced 2–3 mm apart, 2–4 mm diam, male clusters with (1–)5–10 relatively densely crowded flowers, female clusters with 25–35 flowers; bracteoles inconspicuous. Male flowers 4-merous, subsessile, mature buds depressed-globose, c. 1.2 mm diam, tepals without dorsal appendage, hairy, hairs abundant, long, spreading. Stigma 0.8–1 mm long, hooked. Fruiting perianth ovoid, minute c. 0.6 by 0.3 mm, not markedly laterally flattened but with ± distinct marginal rim. Achene more or less filling fruiting perianth.

Distribution ― Burma (Pegu).

Habitat & Ecology ― No certain data available. Probably collected in coastal rainforest or further inland in drier ± forested habitats.

Conservation status ― Critically Endangered (CR). The species is known from only one old collection from the 1800s from Pegu in Burma. No EOO or AOO can be calculated, but the locality is within areas of urban development; we therefore suggest that the species is Critically Endangered with the criteria CR 2Bab(iii).

Note ― This species is easily distinguished from all others in the genus in its entire leaves (the only Old World species known with truly entire leaves with no trace of marginal teeth); however, only one collection is known. The scalariform coarser tertiary venation and conspicuous inflorescence-bracts are distinctive, being similar only to those of B. siamensis , but B. siamensis differs markedly in venation robust rather than slender, leaves serrate, not membranous nor glabrous, often also relatively broader and flower-clusters much more crowded.

Figures

Map 14 Distribution of Boehmeria conica C.J.Chen, Wilmot-Dear & Friis (●), B. polystachya Wedd. (▲) and B. kurzii Hook.f. (ä).

Fig. 13 Boehmeria kurzii Hook.f. a. Upper part of stem with inflorescence-bearing axes; b. leaf, detail of abaxial surface; c. detail of one node with young flower-clusters (inflorescences); d. detail of male part of inflorescence-bearing axis with flower-clusters (inflorescences); e. male bud; f. detail of female part of inflorescence-bearing axis with flower-clusters (inflorescences); g. female perianth in flower; h. fruiting perianth (all: Kurz 3115, K). — Scale bars: a = 2 cm; b–d, f = 2 mm; e, g, h = 1 mm.