Boehmeria manipurensis Friis & Wilmot-Dear

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 : 112

6. Boehmeria manipurensis Friis & Wilmot-Dear — Fig. 5 ; Map 5

Boehmeria manipurensis Friis & Wilmot-Dear in Wilmot-Dear et al. (2010) 438.― Type: Meebold 6253 (holo K), India, Manipur, Irang River , Nov.1907.

Subshrub (habit and height not clear from scarce material); ultimate branches slender, c. 0.7 mm diam, with hairs abundant, short, fine, adpressed. Stipules not seen. Leaves alternate, markedly dimorphic in size and moderately so in shape with ‘larger’ leaves (2–)5–10 × length of ‘smaller’ ones, linear-elliptic and slightly sideways-curved, relatively small c. 5 × 1 cm, length c. 5 × width; margin sharply serrate with 15–20 teeth either side, these up-curved, c. 1 by 3 mm; leaf apex gradually attenuate; base narrowly cuneate; basal veins extending into distal half of lamina and arching and joining upper lateral veins, upper lateral veins slightly dissimilarly arranged on either side, 2 – 3 either side but scarcely distinct from coarser tertiary veins especially on one half, lowest arising near middle of lamina, lateral veins and coarser reticulation deeply impressed adaxially, fine but prominent abaxially; texture thin-coriaceous and leaves slightly bullate, adaxial surface with sparse or abundant hairs, a mixture of coarse adpressed and sparser, longer, finer, spreading; abaxial surface with hairs dense, adpressed or half-adpressed, ± obscuring surface; ‘smaller’ leaves very variable in size relative to adjacent ‘larger’ leaves, sometimes resembling ‘larger’ ones but relatively broader, or sometimes reduced almost to being bractiform, only 2 –3 mm long; all leaves subsessile. Flower­clusters axillary, only female clusters seen, large, 5 –8 mm diam, with well over 100 flowers, these very densely congested forming almost a solid mass; flowers pedicellate and often borne on 2–3-branched peduncles; bracteoles inconspicuous less than half of flower length. Stigma relatively long, 2–3 mm. Fruiting perianth small and narrow, 1–1.2 by 0.3–0.5 mm, spindle-shaped or obovoid to ovoid (varying even on one plant) with short (c. 0.1 mm long) apical beak, always greatly laterally flattened with central part thickened only in distal half or third and surrounded by a marginal wing, this broad, thin-textured; at base long tapering flattened and winged running into the winged pedicel; sparsely hairy near apex, hairs adpressed. Achene narrowly obovoid, 0.5–0.7 by 0.3–0.4 mm, yellow-brown.

Distribution ― India (only known from south-western Manipur).

Habitat & Ecology ― No details certain. Presumably montane forest habitats.

Conservation status ― Data Deficient (DD). The conservation status was discussed by Wilmot-Dear et al. (2010). The species is only known from one single collection made in 1907, and it is presumed to be rare and local, but no conclusions can be drawn as to habitat or conservation status from the minimal label data. The region from which the species has been recorded is remote and under-collected and has still large areas of undisturbed vegetation.

Notes ― 1. This species, which is only known from its type, is distinctive in its combination of alternate small narrow thick-textured markedly dimorphic leaves and very large axillary female clusters with tightly congested pedicellate (often also pedunculate) flowers and long stigmas. Most Old World taxa have opposite leaves and flowers on long leafless axes, and flower-clusters are rarely so large or tightly packed.The material was hitherto misidentified as Pouzolzia sanguinea var. fulgens , probably due to the distinctive leaf characters mentioned above, which are similar to those of that taxon.

2. In habit it is reminiscent of the Philippine B. heterophylla which also has dense sessile clusters and alternate markedly dimorphic sometimes thick-textured leaves (differing in being markedly asymmetrical with hairs spreading rather than adpressed abaxially, not sufficiently dense as to obscure the surface); however, B. heterophylla has a very dissimilar fruiting perianth, sessile, round-based, inflated to dorsiventrally flattened in the distal part giving a ‘shouldered’ appearance (rather than having a distinct marginal wing surrounding a central thickened part) and often entirely without a beak; the achene occupies only the basal half of the fruiting perianth and is markedly asymmetrical, apically swollen on one side with the style asymmetrically inserted.

3. Boehmeria manipurensis could be confused with depauperate material of the often alternate-leaved B. clidemioides (sympatric but widespread) where the diagnostic partly-leafless short lateral inflorescence-bearing axes of the latter are missing; B. clidemioides has a similar fruiting perianth but with a narrower thicker-textured wing and usually sessile; vegetatively it is very variable but its leaves are never coriaceous and are also usually relatively broader and less markedly dimorphic with at least some of the ‘larger’ leaves on a stem petiolate.

Figures

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

Fig. 5 Boehmeria manipurensis Friis & Wilmot-Dear.a.Upper part of stem of fruiting female plant with axillary flower-clusters (inflorescences); b. leaf; c. leaf, detail of adaxial surface; d. detail of abaxial surface; e. axillary female flower-cluster (inflorescence); f–h. fruiting perianths of different form (f, g from same plant); i. fruit with perianth removed (a–g, i: Mee­ bold 6253; h: McClelland s.n.; all K). — Scale bars: a = 2 cm; b = 5 mm; c, d, f–h = 1 mm; e = 2 mm; i = 0.5 mm.