Boehmeria virgata var. canescens, 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 : 164-166

i. var. canescens (Wedd.) Friis & Wilmot-Dear , comb. nov. — Fig. 24p , 25 ; Map 26

Basionym: Boehmeria platyphylla D.Don var. cuspidata Wedd. subvar. canescens Wedd.,Archiv. Mus. Hist. Nat. Paris 9 (1856) 365. ― Boehmeria canescens Wedd.(1854) 200,nom nud. ― Boehmeria canescens (Wedd.) Blume (1857) 224. ― Boehmeria platyphylla D.Don var. canescens (Wedd.) Wedd. (1869) 213. ― Boehmeria macrophylla Hornem. var. canescens (Wedd.) D.G. Long (1982) 129. ― Boehmeria macrophylla Hornem. subsp. canescens (Wedd.) Panigrahi & Murti (1999) 558. ― Type: Wallich 4582D (lecto K; isolecto BM, G, K [non K-WALL]; lectotype selected here), Nepal. – See Note 3.

Subshrub, to 2 m. Stems with two kinds of indumentum, abundant fine hairs 0.2–0.4 mm long, close-adpressed, inconspicuous, and coarser longer (c. 1 mm) hairs spreading, curved hairs, the latter sparse or absent in lower part of stem but dense at upper nodes and stem apex and concealing the adpressed hairs. Stipules 6–9 mm long, with adpressed hairs on abaxial surface and long hairs only on midrib. Leaves ovate-elliptic, with a wide size range 4.5–16 by 3–12 cm, length 1.3–1.8 × width, rather variable in proportions and in number of marginal teeth, marginal teeth (22–)25–45(–50) either side, small narrow-acute up-curved, 2–3 by 2–3.5(–5.5) mm, with width 1–1.25(–1.75) × length; leaf apex short-attenuate or with indistinct short acumen 2–5 mm long, toothed nearly to tip; base slightly asymmetrical, cuneate or narrowly(-broadly) rounded; texture thin-chartaceous, adaxial surface with long curved hairs like those on the stem, sparse or abundant, abaxial surface with spreading hairs of varying lengths, these usually abundant giving whitish cast to leaf; petiole rather variable (0.25–)0.3– 0.6 × lamina length, hairy like the stem. Inflorescence-bearing axes 10– 20 cm, pendulous with a few long branches near base, or sometimes male ones ≤ 5 cm and ± erect with drooping branches, always very slender, only 0.2–0.4 mm diam (in dry state); both sexes on same plant, male in lower axils; flower-clusters rarely ± contiguous, mostly spaced 0.5–1(–2) mm apart, c. 1.5–1.75 mm diam, male clusters with few ± sessile flowers, female clusters with less than 30 flowers often with pedicel to c. 0.5 mm long and flowers often borne a few together on minute peduncles (up to c. 1 mm long) which are flattened, strap-shaped; clusters rather elongate (due to the region of insertion of the peduncles onto the stem being unusually long and narrow). Fruiting perianth small c. 0.5 by 0.25–0.3 mm, narrowly ellipsoid with base rounded or tapering and running into pedicel, with fine hairs near apex or throughout. Achene almost filling fruiting perianth.

Distribution ― Eastern Himalayas: India (Sikkim, Arunachal Pradesh), Nepal, Bhutan.

Habitat & Ecology ― Mixed forest, 1800 m altitude.

Notes ― 1. As discussed in detail under the species as a whole (Note 5-vii), it is distinctive in its extremely slender inflorescence-bearing axes, its minute female perianth, two kinds of indumentum abundant on the stem and the white cast to the abaxial leaf surface (where present). Pedicellate and pedunculate female flowers are otherwise seen only in var. minuticymosa .

2. Even the few collections seen (only 11 clearly referable to var. canescens ) are rather variable and probably do not represent its full range of variation.A few collections have been seen intermediate with var. rotundifolia and var. minuticymosa , and formal conservation status assessment is not meaningful. The variety is thought to be rare as it is so far only known from a few locations along the Himalayas, and in fairly restricted forest habitat, but is probably not currently at risk since these localities in the Himalayas are not currently threatened by serious habitat degradation.

3. The specimens at K and K-WALL labelled Wallich 4582D both have inflorescence-bearing axes slender, pendulous and marginal teeth many, rather narrow, but appear to represent different collections since they differ markedly in stem indumentum. The indumentum on the K specimen is of two kinds, long spreading hairs sufficiently dense in the upper part of stem as to conceal an under-layer of also dense but much shorter and finer adpressed hairs, while that of K-WALL lacks the spreading indumentum. Only the K specimen has leaves with sufficiently dense indumentum to conform well to Weddell’s description “leaves ... canescent” and it is therefore here selected as the lectotype. (By contrast, another specimen, Nepal, 1831, Wallich 4582 (K), without the letter ‘D’ as suffix to the number, very closely resembles the lectotype and may be an isolectotype). The numbering of the K-WALL specimen is somewhat doubtful since it is annotated by C.B. Clarke merely “Napalia, 4582“; the ‘D’ and the epithet canescens were inserted by Hooker who also states there and in Hooker (1888) 579, that “Herb Madras” in Herb. Wallich is probably an error. This specimen and a possible duplicate of it at E also labelled Wallich 4582D with a few spreading hairs at stem apex, are best considered as somewhat intermediate, possibly with var. minuticymosa . (A further specimen in K-WALL, “4582?D” is a mixture of leaves and inflorescence from different taxa, one leaf probably of B. nivea ; none of its material conforms to the K specimen.)

Figures

Map 26 Distribution of Boehmeria virgata (G.Forst.) Guillem. subsp. macrophylla (Hornem.) Friis & Wilmot-Dear var. canes­ cens (Wedd.) Friis & Wilmot-Dear.

Fig. 24 a–i: Boehmeria virgata subsp. macrophylla var. macrostachya (Wight) Friis & Wilmot-Dear. a. Habit of stem with inflorescence-bearing axes; b. leaf, detail of adaxial surface;c. leaf, detail of abaxial surface;d. detail of stem and stipules;e. detail of male inflorescence-bearing axis and flower-clusters (inflorescences); f. male bud; g. detail of female inflorescence-bearing axis and flower-cluster (inflorescence); h, i. fruiting perianths of different form (from different plants). — j–o: Boehmeria virgata subsp. macrophylla var. scabrella (Roxb.) Friis & Wilmot-Dear. j. Habit of stem with branched inflorescence-bearing axes; k. leaf; l. leaf,detail of adaxial surface; m. leaf, detail of abaxial surface;n. detail of stem and stipules; o. fruiting perianth. — p: Boehmeria virgata subsp. macrophylla var. canescens (Wedd.) Friis & Wilmot-Dear. Leaf, detail of adaxial surface (a–c, h: Gamble 9034; d, i: Haines 5068; e, f: Haines 2309; g: Clarke 34129; j: Schiffner 1900; k, n: Hooker & Thompson s.n.; l, m, o: Ford 173; p: Wallich 4582; all K). — Scale bars: a, j, k = 2 cm; b-d, l-n = 2 mm; e-h, i, o = 1 mm.

Fig. 25 Boehmeria virgata subsp. macrophylla var. canescens (Wedd.) Friis & Wilmot-Dear. a. Habit of stem with inflorescence-bearing axes; b. leaf, detail of adaxial surface; c. leaf, detail of abaxial surface; d. detail of stem and stipules; e. detail of male inflorescence-bearing axis with flower-clusters (inflorescences) and bracts; f. male bud; g. detail of female inflorescence-bearing axis with flower-cluster and bract; h. pedicellate fruiting perianth (a, d, g, h: Kanai 6307148, BM; b, c: Wallich 4582, K; e, f: Wallich 4582D, K). — Scale bars: a = 2 cm; b–d = 2 mm; e-h = 1 mm.