Boehmeria japonica var. tenera, 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 : 193-195

c. var. tenera (Blume) Friis & Wilmot-Dear , comb. nov. — Fig. 35 ; Map 37

Basionym: Boehmeria spicata (Thunb.) Thunb. var. tenera Blume (1857) 220. ― Type: Unknown collector s.n. L 908.186–164 (holo L, according to Yahara 1984a: 130), Japan .

Urtica spicata Thunb.(1784) 69. ― Boehmeria spicata (Thunb.)Thunb. (1794b) 330, nom. illeg. superfl. (see Note 1 under species as a whole). ― Type: Herb. Thunb. 22115 (lecto UPS-THUNB, selected by Yahara 1984a: 130), Japan .

Boehmeria spicata (Thunb.) Thunb. var. akari Blume (1857) 220. ― Type: Unknown collector s.n. (holo L, 908.186-156; iso K), Japan.

Boehmeria gracilis C.H.Wright (1899) 485. ― Syntypes: Henry 4692 (K; isosyn A), 4728 (syn K), China, Hubei, Patung; Henry 6258 (K), China, Changlo. – See Note 6 under the species as a whole.

Boehmeria spicata (Thunb.) Thunb.var. microphylla Nakai ex Satake (1936) 483. ― Type: Nakai s.n. (holo TI), Japan, Honsyu, 26 June 1931. – See Note 3.

Boehmeria paraspicata Nakai ex Satake (1936) 483. ― Type: G. Koidzumi s.n. (holo TI), Japan, Hokkaido, Isikari Prov. , Aug. 1916. – See Note 7.

Boehmeria paraspicata Nakai ex Satake forma viridis Satake (1936) 485. ― Type: Hisauchi s.n. (holo TI), Japan, Honshu, Sagami, 19 July 1931. – See Note 7.

Boehmeria tricuspis (Hance) Makino var. unicuspis Makino (1948) 641, nom. nud. – See Note 6.

Boehmeria hwaliensis Y.C.Liu & F.Y.Lu in Lu (1978) 100. ― Type: Liu & Ou 1741 (holo TCF, digital image seen), Taiwan, Hualien, Luan Shan .

Boehmeria densiflora sensu Chen , non Hook. & Arn. ( Chen et al. 2003: 175). – See Note 4.

Usually a herb, sometimes a subshrub, to 1 m. Stems with fine adpressed hairs, soon glabrescent. Leaves ovate or rhombic-ovate, small or medium, 2–9(–14) by 1–4(–8) cm, length (1.6–)1.8–2.7 × width; marginal teeth only 6–10(–12) either side, those near apex sometimes only 1.5–2 × length of those near base but then all teeth markedly up-curved and relatively long relative to size of leaf (tooth depth often a quarter of total distance to midrib); outline of apex gradually narrowing towards a single long ± linear terminal tooth which often (especially in largest leaves) comprises a third to half of lamina length; base cuneate to truncate; texture membranous or very thin-chartaceous, adaxial surface with hairs like stem, often soon glabrescent, abaxial surface often ± glabrous. Inflorescence-bearing axes 5–10(–15) cm long, glabrous or hairs sparse, adpressed or spreading; fruiting clusters usually well-spaced, 2–4 mm diam. Male tepals with or without dorsal appendage. Fruiting perianth 1–2 by 0.6–1.2 mm, winged or not.

Distribution ― China (including Taiwan, but excluding the southernmost part of the mainland), South Korea, Japan (Honshu, Shikoku, Kyusyu).

Habitat & Ecology ― Forest margins,thickets,streams,grassland; 100–2050 m altitude.

Notes ― 1. Var. tenera is distinctive in being glabrous or sparsely adpressed-hairy with thin-textured leaves, as in var. silvestrii but leaves small ovate, acuminate, with marginal teeth few and relatively long. Var. tenera appears to be more common than var. silvestrii (many more collections seen) and to extend to drier habitat. It is absent from northern Japan (Hokkaido) but recorded further southeast in China than var. silvestrii . Like var. silvestrii it occurs further north in China than does var. japonica .

2. The interpretation of the variation within this variety is discussed fully under the species as a whole (see Note 6). As discussed above under the species as a whole (see Note 7, 8), few intermediates with either var. silvestrii or var. japonica have been seen compared to the large number of collections clearly referable to this taxon.

3. Yahara (1984a: 130, 132) tentatively maintained var. microphylla differing apparently ( Okabe 1956) in its chromosome number (2n = 28) from typical var. spicata (2n = 42), but stated that its “separation … as a distinct variety of diploid remains an assumption because the correlation between ploidy level and phenetic features is not fully understood yet”. We here consider it as representing one extreme of a continuous range of variation in leaf-size shown by var. tenera .

4. The photo under B. hwaliensis in Yang et al. (1996: 202, 785 photo 79) does not conform to the type material but to that of B. minor (small-leaved var. japonica ).

5. Confusion with B. virgata subsp. macrophylla var. densiglomerata and B. sieboldiana is discussed under the species as a whole (see Notes 12 & 15).

6. According to Yahara (1983a: 261) the name B. tricuspis var. unicuspis was widely used in Japanese floristic literature but never validly published.

7. Boehmeria paraspicata and B. paraspicata forma viridis , and names based on these, represent forms closest to this taxon although their leaves are rather broad; they possibly represent forms intermediate with var. silvestrii .

Figures

Map 37 Distribution of Boehmeria japonica (L.f.) Miq. var. tenera (Blume) Friis & Wilmot-Dear.

Fig. 35 Boehmeria japonica var. tenera (Blume) Friis & Wilmot-Dear. a. Habit of stem with unbranched inflorescence-bearing axes; b. leaf; c. leaf, detail of adaxial surface and margin; d, e. leaf, detail of abaxial surface from different plants; f. detail of stem and stipule; g. detail of male inflorescence-bearing axis with two flower-clusters (inflorescences); h. male bud; i. detail of female inflorescence-bearing axis with two flower-clusters (inflorescences); j, k. fruiting peri- anths from different plants (a, e, f, i: Farges 608; b-d: Henry 4728; g, h: Furuse 42315; j: Silvestri 400; k: Cheng 201; all K). — Scale bars: a = 2 cm; b = 1 cm; c-e = 2 mm; f -k = 1 mm.