Phyllanthus ussuriensis Rupr. & Maxim.

Verwijs, J. I. M., Bouman, R. W. & Welzen, P. C. van, 2019, A taxonomic revision of Phyllanthus subgenus Macraea (Phyllanthaceae), Blumea 64 (3), pp. 231-252 : 247

21. Phyllanthus ussuriensis Rupr. & Maxim. — Map 13

Phyllanthus ussuriensis Rupr. & Maxim. (1857) 222; P.T.Li & M.G.Gilbert (2008) 182. — Phyllanthus anceps Benth. (1861) 311, nom. illeg., non Phyllanthus anceps Vahl ; F.B.Forbes & Hemsl. (1894) 420. — Phyllanthus simplex Retz. var. ussuriensis (Rupr. & Maxim.) Müll.Arg. (1863) 33; (1866) 392. — Phyllanthus wilfordii Croizat & F.P.Metcalf (1942) 194, nom. superfl. — Type: C.J. Maximowicz s.n. (holo probably LE; iso K, M, NY), Russia, Ussuri.

Phyllanthus simplex Retz. var. chinensis Müll.Arg.(1863) 33; (1866) 391. — Phyllanthus virgatus G.Forst.var. chinensis (Müll.Arg.) G.L.Webster (1971) 68. — Syntypes: Park 57 (G-DC), China, Canton; Hance 1223 ( B, presum- ably lost), China, Hongkong ; C. Wilford 66 ( A), China, Hongkong .

Phyllanthus matsumurae Hayata ex Y.Yabe (1904) 12. — Type: Not designated.

Erect herbs, 10‒45 cm high, monoecious; branches brown, glabrous, minutely ridged, distally flattened and winged; internodes 3‒13 mm long. Stipules triangular, 1‒1.2 by 0.5‒0.8 mm, base cordate, margin entire or serrate, apex attenuate. Leaves: petiole c. 0.5 mm long, glabrous; blade elliptic, 4‒25 by 1.5‒8 mm, 2.4‒5 times longer than wide, glabrous, green, base obtuse, rounded or minutely cordate, sometimes slightly asymmetrical, margin not thickened, slightly revolute, apex obtuse or acute, rarely rounded; midrib prominent on both sides, lateral veins 4‒9 per side, prominent on both sides. Staminate flowers solitary to 3 together, 0.8‒1 mm diam; pedicel c. 1 mm long, glabrous, slender; sepals 4 or 6, ovate or oblong, c. 0.4 by 0.2 mm, apex rounded; disc glands 4 or 6, cupuliform, c. 0.1 mm diam, c. 0.1 mm high; stamens 2 or 3 (often on the same plant), c. 0.4 mm long, filaments free, reflexed, thecae ovoid, c. 0.2 mm long. Pistillate flowers with 1 or 2 staminate flowers, rarely solitary, c. 1 mm diam; pedicel c. 1 mm long, glabrous; sepals 6, ovate, 0.3‒0.8 by c. 0.2 mm, apex rounded; disc glands 6, alternate, protruding from between the sepals, ovate or oblong, 0.15‒0.2 by c. 0.1 mm, flat; ovary sessile, globular, c. 0.8 mm diam, c. 0.5 mm high, glabrous or verrucate; style very short, stigmas 3, c. 0.3 mm long, bifid for 1/2 of the length, reflexed. Fruits subglobular, 2‒2.5 mm diam, 6-grooved, sometimes bivalved, glabrous or verrucate; pedicel 2‒3.5 mm long, glabrous; stigmas, sepals and disc glands persistent; columella c. 1 mm long. Seeds c. 1 by 1 mm, smooth or minutely verrucate, dark or chestnut-brown, verrucae small, very prominent and randomly placed.

Distribution — Southeast Russia, China, Japan.

Habitat & Ecology — Near rivers and ponds, in moist places under woods. Altitude: 45‒630 m. Flowering: June to October.

Uses — All parts are used as an astringent or antidiarrheal ( Li & Gilbert 2008, Quattrochi 2016).

Vernacular names — China: Mi gan cao (), Sweet orange grass (Chinese, mandarin, Li & Gilbert 2008).

Note — This is the only species in subgen. Macraea with staminate flowers with 4 sepals, 2 stamens and 4 disc glands, though staminate flowers with 6 sepals, 3 stamens and 6 disc glands also occur, often on the same plant. The 6 disc glands of the pistillate flowers, while not a unique character, distinguish this species from the vegetatively very similar P. virgatus , which has an annular disc in its pistillate flowers.

Figures

Map 13 Distribution of Phyllanthus ussuriensis Rupr. & Maxim. in E Asia.