Elatostema retrohirtum Dunn, Bull. Misc. Inform. Kew, Addit. Ser. 10: 249. 1912.

Xin, Zi-Bing, Monro, Alexandre K., Wang, Ren-Fen & Fu, Long-Fei, 2023, An integrative approach to species delimitation sinks three Chinese limestone karst Elatostema (Urticaceae) species, PhytoKeys 236, pp. 83-96 : 83

Elatostema retrohirtum Dunn, Bull. Misc. Inform. Kew, Addit. Ser. 10: 249. 1912.

= Elatostema robustipes W.T.Wang, F.Wen & Y.G.Wei, Ann. Bot. Fenn. 49: 188. 2012. Syn. nov. Type: China. Guangxi: Huanjiang County, Mulun National Reserve, Hongdong, alt. 308-512 m, 24°43'N, 108°18'E, 26 April 2009, Y.G. Wei 124 (holotype: IBK!; isotypes: IBK!, PE [PE01843378!, PE01843379!]).

Type.

China. Guangdong: near Yit-hai Han valley , Dunn’s Han Exped., Herb. Hongk. no. 6288 (holotype: K!) .

Description.

Perennial herb. Stems 150-350 × 1.8-2.5 mm, ascending or erect, branched, densely hispid, the hairs weakly curved to crooked, appressed; stipules 2, linear-lanceolate, 4-8 × 1.0-2.0 mm, cystoliths sparsely scattered, glabrous. Leaves sessile or short petiolate, petioles 0-1(-4.5) mm, densely hispid, the hairs weakly curved to crooked, appressed; laminae 40-60(-100) × 15-20(-50) mm, obliquely elliptic, herbaceous or chartaceous, triplinerve; cystoliths densely scattered; base asymmetrical, broader-half rounded or auriculate, narrower-half cuneate; margin denticulate; apex short acuminate or acute, rarely acuminate. Staminate inflorescences solitary, capitate; peduncle 3.5-6.0 × 0.3-0.8 mm, sparsely hispid, the hairs weakly curved, appressed; receptacle 2-4 × 3-5 mm, rectangle or oblong, glabrous, subtended by marginal bracts; the bracts ca. 6, unequal, outer 2 bracts major, broadly ovate, 2-2.5 × 4-5 mm, abaxial surface sparsely hispid, the hairs weakly curved, appressed, with 5 or 6 longitudinal ribs, each ribbed extending apically as a corniculate protuberance, inner 4 bracts minor, obovate, ca. 2 × 3 mm, abaxial surface with 1-3 longitudinal ribs, at least one ribbed extending apically as a corniculate protuberance, glabrous; staminate flowers pedicellate, glabrous; bracteoles 2 per flower, equal, 2.5-4.0 × 1.0-1.5 mm, oblanceolate or obovate, glabrous; tepals 4, ovate, 0.9-1.2 × 0.7-0.9 mm, subapical appendage ca. 0.5 mm, corniculate, glabrous. Pistillate inflorescence solitary, capitate; peduncle ca. 1 × 0.5 mm, glabrous; receptacle subrounded, 3-3.5 mm in diam., glabrous, subtended by marginal bracts, the bracts numerous, subequal, triangular, 0.6-1.2 × 0.4-0.6 mm; pistillate flowers pedicellate; bracteoles 2 per flower, subequal, ca. 0.6-1.2 × 0.3 mm, spatulate-linear; achenes 0.5-0.6 mm, ovoid or ellipsoidal, ca. 6-ribbed.

Distribution.

This species is distributed in China (Guangdong, Guangxi, Guizhou, Sichuan, Yunnan) and Vietnam (Bac Kan, Gia Lai, Ha Giang, Ha Noi, Hai Phong, Hoa Binh, Lam Dong, Nghe An, Ninh Binh, Son La, Tuyen Quang).