Boehmeria virgata var. sumatrana, 2013

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 : 171-173

m. var. sumatrana (Miq.) Friis & Wilmot-Dear , comb. nov. — Fig. 28a–e ; Map 29

Basionym: Boehmeria sumatrana Miq. , Plantae Junghuhnianae, Pars 1 (1851) 32. ― Boehmeria platyphylla D.Don var. virgata (G.Forst.) Wedd. subvar. sumatrana (Miq.) Wedd. (1856) 367. ― Boehmeria platyphylla D.Don var. sumatrana (Miq.) Wedd. (1869) 211. ― Type: Junghuhn s.n. (holo U; iso BO, L), Indonesia, Sumatera, Tapanuli, Sipirok plain, Warseh, Battarum Dist.

Subshrub or possibly shrub (height unknown). Stem with hairs 0.2–0.4 mm long, sparse to abundant, closely-adpressed, fine, straight. Stipules usually relatively long, 7–10 mm. Leaves broadly ovate (deltate-ovate), small or medium, 5.5–10 by 4–8.5 cm, length only 1.1–1.3(–1.4) × width; margin dentate, teeth only 13–17, relatively short and broad, 2–3 by 5–6 mm, with width (1.5–)2–3 × length, of ± uniform size but proximal ones progressively less up-curved, those near apex with their upper margin distinctly concave, those near base often ± rounded and outward-pointing (both margins convex); leaf apex with short abrupt acumen, (5–) 10–15 mm long, consisting mostly of single tooth; base truncate or ± cordate, rarely broadly rounded; texture very thin-chartaceous; both surfaces with rather sparse fine adpressed hairs like the stem; petiole variable but extremely long relative to lamina, 0.6–1.2 × lamina length. Inflorescence-bearing axes ± erect and mostly bisexual, sometimes unbranched and relatively long, 8 –12 cm, sometimes with lateral branches throughout lower half and then often shorter, 5 –8 cm, distal clusters female, proximal ones and those on lateral branches often bisexual, some lower lateral branches and some axes in lower leaf axils entirely male; clusters contiguous (but distinguishable) or spaced up to 1(–2) mm apart, only 1–2 mm diam, with few–10(–20) flowers. Fruiting perianth ovoid to obovoid flattened or inflated in distal part but without distinct marginal rim, c. 0.8 mm long, almost without beak, hairy like stem.

Distribution ― Indonesia (western Sumatera).

Habitat & Ecology ― No label data but the localities are within the ridge of mountains in western Sumatera, so it is assumed to inhabit forest at fairly high altitude .

Conservation status ― Near Threatened (NT). The lack of habitat data for this well-circumscribed variety makes formal assessment tentative. It is known from only six collections from the early 1900s from three localities, with an EOO of only 2 343 km 2 and AOO of only 12 km 2. Habitat in this region is apparently not currently seriously degraded and Kerinci [Kerinchi] has protected status but with so few collections it is probably at risk.

Notes ― 1. This variety is apparently allopatric to the rest of the subspecies (and species). As discussed (Note 5-xi–xiii under the species as a whole), this and the following two varieties, var. densiglomerata and var. strigosa , are distinctive in leaf shape, texture and indumentum; var. sumatrana is distinguished from the other two on morphology of the inflorescence-bearing axes and marginal teeth, and sparse indumentum.

2. Little material has been seen, possibly not reflecting the full range of variation. One less distinctive collection has been seen with obtuse marginal teeth and lacking the distinctive cordate base but otherwise conforming to this variety: Sumatera, Kerinchi, Robinson & Kloss Apr. 1914 (BM). The material represents a small herb to 60 cm with leaves 4–9 by 2.5–6 cm, length c. 1.5 × width, margin crenate-dentate (i.e., teeth obtuse although still up-curved with their upper margin concave), base broadly rounded to broadly cuneate and inflorescence-bearing axes 12 cm, unbranched, mainly female, with scattered male flowers throughout length.

Figures

Map 29 Distribution of Boehmeria virgata (G.Forst.) Guillem.subsp.macro­ phylla (Hornem.) Friis & Wilmot-Dear var.scaberrima (Roxb.) Friis & Wilmot- Dear (●), B. virgata (G.Forst.) Guillem. subsp.macrophylla (Hornem.) Friis & Wilmot-Dear var.sumatrana (Miq.) Friis & Wilmot-Dear (▲) and intermediates between B. virgata subsp. macrophylla var.scaberrima and B. virgata subsp. macrophylla var. macrostachya (ä).

Fig. 28 a–e: Boehmeria virgata subsp. macrophylla var. sumatrana (Miq.) Friis & Wilmot-Dear. a. Habit of stem with branched bisexual inflorescence-bearing axes with flower-clusters (inflorescences); b. detail of stem with unbranched female inflorescence-bearing axis; c. leaf, detail of abaxial surface;d. detail of stem and stipules; e. detail of lower part of branched bisexual inflorescence-bearing axes. — f–l: Boehmeria virgata subsp. macrophylla var. strigosa (W.T.Wang) Friis & Wilmot-Dear. f. Habit of stem with branched bisexual inflorescence-bearing axes with flower-clusters (inflorescences); g, h. leaves from different plants; i. leaf, detail of abaxial surface; j. detail of stem and stipules; k, l. fruiting perianths (from different plants) (a, c-e: Praet s.n., L; b: Bunnemeijer 4828, L; f, j, k: Chow & Wai 79126, E; g, l: Balansa 595, K; h, i: Cuong 150, L). — Scale bars: a, b, g, h = 2 cm; c–e, i, j = 2 mm; f = 10 cm; k, l = 1 mm.