Boehmeria virgata var. tomentosa, 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 : 162

f. var. tomentosa (Wedd.) Friis & Wilmot-Dear , comb. nov. — Fig. 23i–l ; Map 24

Basionym: Boehmeria tomentosa Wedd. in Annales des Sciences Naturelle, Sér. 4, Botanique, Vol. 1 (1854) 200. ― Boehmeria platyphylla D.Don var. tomentosa (Wedd.) Wedd.(1856) 367. ― Boehmeria macrophylla Hornem. var. tomentosa (Wedd.) D.G. Long (1982) 130. ― Type: Chapelier s.n. (lecto P, selected here as part of the original material best conforming to the original description), Madagascar.

Non Boehmeria tomentosa sensu auct., which is B. ourantha . – See Note 2.

Low subshrub branching from base, up to 1.5 m tall; ultimate stems very robust, 2 – 3 mm diam, with hairs dense, spreading, stiff, straight, pale or brownish, 0.4–0.7(–1) mm long, often so dense as to completely obscure surface, persistent on older branches. Stipules 8–11 by 2–2.5(–3) mm, fairly thick-textured, hairy abaxially. Leaves scarcely or markedly dimorphic in size with length of ‘larger’ lamina 1.1–2 × length of ‘smaller’, rhombic-ovate ( Nigeria) to broadly ovate ( Cameroon, Madagascar), medium, 8–12(–16) by 3.5–6(–10) cm, length (1.6–)1.75–2 × width; margin dentate, teeth 30–40 either side, shallow, distal ones sometimes slightly up-curved, (1–)1.5–3 by 1.5–3.5(–6) mm; leaf apex attenuate-acuminate or abruptly short-acuminate consisting mostly of a single tooth c. 1 mm long; base broadly cuneate to rounded, sometimes narrowly subcordate; texture thick-chartaceous to thin-coriaceous; both surfaces velvety with dense spreading indumentum like the stem, or ( Cameroon, Madagascar) hairs half-adpressed and sparser adaxially; veins robust; petiole variable but often very short relative to lamina, 0.1–0.3(–0.4) × lamina length. Inflorescence-bearing axes pendulous, sometimes bisexual, 15– 30 cm long, female unbranched, male and bisexual branched or not; clusters mostly unisexual, almost contiguous to well-spaced, male clusters very variable in size, 2.5–4 mm diam, with less than 10–more than 40 flowers; female clusters 2–3.5 mm diam (3–4 mm in fruit), with 30–more than 50 flowers. Male and female flowers densely hairy. Fruiting perianth relatively large and broad, ovoid to ellipsoid, c. 1.5 by 1 mm, with tapering or broadly rounded base and acute apex without beak, moderately laterally flattened in fruiting part and with either winged ‘shoulders’ or narrow marginal rim around achene, with dense short spreading dark brown pubescence. Achene ± filling fruiting perianth.

Distribution ― Africa ( Nigeria, Cameroon, Congo Republic, Uganda, Tanzania, Zambia), Madagascar, Comoro Islands, Reunion.

Habitat & Ecology ― Open dry rocky hillsides, savannah, disturbed land (millet cultivation terraces); 1250–3500 m altitude.

Notes ― 1. Formal conservation assessment is not given for this variety which intergrades with the typical one. Only c. 30 collections have been seen clearly referable to this variety but it is widespread and not considered at risk.

It appears to be a dry-habitat variant of var. molliuscula , distinctive in indumentum and leaf texture and uncommon compared to var. molliuscula . As discussed under the species as a whole (Note 5-ii) the two taxa intergrade, with many intermediate collections seen mostly from more moist habitat.

2. According to our circumscription and lectotypification the epithet tomentosa has been persistently misapplied to a very different Southeast Asian entity for which the name B. ourantha Miq. (1851: 33) already existed. Weddell (1856: 367) appears to have assumed the South-east Asian material to be conspecific with his earlier-described Malagasy species B. tomentosa ( Weddell 1854: 200) . Hochreutiner (1925), in making the combination B. platyphylla var. ourantha , noted the Asian material as distinct from the Malagasy entity bearing the epithet ‘ tomentosa ’ but the misapplication of the epithet ‘ tomentosa ’ to material of B. ourantha continued in much subsequent literature (e.g., Chen et al. 2003: 170). Most confusingly, the combination B. macrophylla Hornem. var. tomentosa (Wedd.) D.G. Long (1982: 130) was made in the Flora of Bhutan due to this misapplication (see discussion under B. ourantha , Notes 3 and 4). This validly published new combination as a variety under B. platyphylla (= B. virgata var. macrostachya in our sense) was applied to Bhutanese material of B. ourantha . This Southeast Asian species, B. ourantha , is easily recognised by its distinctive inflorescence architecture with male flowers pedicellate and scattered along unbranched mainly female inflorescence-bearing axes or in a few clusters at their apex (rather than on short lateral side branches near the base); female and bisexual inflorescence-bearing axes are also short mostly ≤ 10 cm (rather than ≥ 15 cm) with clusters larger and more densely crowded. Boehmeria ourantha is also distinctive in its indumentum golden-brown, often very long (up to 2 mm), giving a distinct golden-brown rather than pale sheen to plant, leaves broader, often crenate, not distinctly acuminate, base often truncate and marginal teeth fewer and often larger.

Figures

Map 24 Distribution of Boehmeria virgata (G.Forst.) Guillem.subsp.macro­ phylla (Hornem.) Friis & Wilmot-Dear var.molliuscula Blume) Friis & Wilmot- Dear () and B. virgata (G.Forst.) Guillem. subsp. macrophylla (Hornem.) Friis & Wilmot-Dear var. tomentosa (Wedd.) Friis & Wilmot-Dear (●).

Fig. 23 a–c: Boehmeria virgata subsp. virgata var. austroqueenslandica (Domin) Friis & Wilmot-Dear. a. Leaf; b. detail of stem and stipules; c. fruiting perianth. — d–h: Boehmeria virgata subsp. macrophylla var. molliuscula (Blume) Friis & Wilmot-Dear. d. Leaf; e. leaf, detail of adaxial surface; f. leaf, detail of abaxial surface; g. detail of stem and stipules; h. fruiting perianth. — i–l: Boehmeria virgata subsp. macrophylla var. tomentosa (Wedd.) Friis & Wilmot-Dear. i. Leaf; j. leaf,detail of abaxial surface;k. detail of stem and stipules; l. fruiting perianth.— m–o: Boehmeria virgata subsp. macrophylla var. longissima (Hook.f.) Friis & Wilmot-Dear.m. Habit of stem with inflorescence-bearing axes; n. detail of stem and stipules;o. fruiting perianth (a–c: Melville & Hunt 3628; d–h: Manning 2007; i, j: McClintock 147; k, l: Daramola 67450; m, o: Gamble 1260B; n: Bourne s.n.; all K). — Scale bars: a, d, i, m = 2 cm; b, e-g, j, k, n = 2 mm; c, h, l, o = 1 mm.