Boehmeria heterophylla var. blumei

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 : 110

1. Hairs on stem of two distinct kinds, minute, <0.1 mm long, spreading and longer (c. 0.5 mm long), curved; leaves often subopposite, often thicker-textured and/or bullate or relatively broader (length 2.5–4.5 × width), marginal teeth with convex upper margin.................. b. var. blumei a. var. heterophylla — Fig. 4e–j ; Map 7

Boehmeria cumingiana Blume (1857) 199. ― Type: Cuming 1561 (holo L; iso G, M, P), Philippines. – See Note 1.

Ultimate stems slender, up to 1 mm diam, with abundant hairs, these fine, adpressed or half-adpressed, straight, up to 0.2 mm long, sometimes later glabrescent. Leaves alternate, the ‘larger’ ones 3 –10 × length of ‘smaller’ ones; ‘larger’ leaves slightly or markedly asymmetrical, narrowly ovate or linear-lanceolate, (6–)8–16 by 1.4–4 cm, length (3–)4–5(–6) × width; margin with up to 35 teeth either side, these acute, broad, shallow, 1–2(–3) by 2–3(–6) mm, with their upper margin concave, base asymmetrically rounded or slightly cuneate; texture very thin-chartaceous, adaxial surface with hairs abundant, more or less adpressed, longer than on stem, abaxial surface with hairs sparse or abundant longer, more or less spreading; petiole short but variable relative to size of lamina, 0.1–0.3 × lamina length, pubescent like stem, sometimes also with longer spreading hairs. Female flower­clusters up to 5 mm diam, with 50 - 70(- 100) densely crowded flowers; bracteoles up to 0.8 mm long, rounded. Male flowers sessile. Stigma 1–1.4 mm long, extremely slender. Fruiting perianth 1–1.2 by c. 0.6 mm. Achene 0.7–1 by c. 0.4–0.6 mm, (excluding apical stylar projection).

Distribution ― Philippines (Luzon, Mindanao, Mindoro, Panay), Indonesia (Papua), Papua New Guinea.

Habitat & Ecology ― Margins of evergreen forest adjoining riverine forest; secondary forest; 200–500 m altitude.

Notes ― 1. The holotype of B. cumingiana belongs to the same collection as B. heterophylla but represents a different duplicate.

2. This variety is very variable in leaf shape. See under the species for discussion of differences from var. blumei .

3. There is some regional variation. In Mindanao, as well as more ‘typical’ material, small-leaved collections have been seen with stipules short and relatively broad, acute rather than acuminate (length only 3 × rather than 4 × width). In Mindoro, the only 3 collections seen differ in young fruiting perianth having apparently a long and narrow achene nearly as long as the fruiting perianth, and a broad marginal winged region as well as an apical winged region. However, the fruiting perianths of these specimens are too immature to determine its adult form, and as the material vegetatively falls within the above range of variation and is therefore included here.

Figures

Map 7 Distribution of Boehmeria heterophylla Wedd. var. heterophylla.

Fig. 4 a–d: Boehmeria beyeri C.B.Rob. a. Part of stem showing leaves dimorphic in petiole length; b male flower; c. axillary female flower-cluster (inflo- rescence); d. female perianth. — e–j: Boehmeria heterophylla Wedd. var. heterophylla. e. Stem with alternate dimorphic leaves and axillary flower-clusters (inflorescences); f. detail of stem with fine adpressed indumentum; g. leaf with adpressed indumentum on adaxial surface; h. axillary female flower-cluster (inflorescence); i, j. fruiting perianths of different form (from same plant).— k–m: Boehmeria heterophylla var.blumei (Wedd.) Friis & Wilmot-Dear.k. Stem with subopposite dimorphic leaves; l. detail of stem with coarse and fine spreading indumentum; m. male flower in bud (a–d: Beyer 13540; e: Cuming 1561; f, h: Borbon 8866; g: Elmer 15627; i, j: Edano 19876; k, l: Cuming 731; m: PPI 11815; all K). — Scale bars: a, e, g, k = 2 cm; c, h = 2 mm; b, d, f, i, j, l, m = 1 mm.