Elatostema multicaule W.T.Wang, Y.G.Wei & A.K.Monro, 2011

Wei, Y. G., Monro, A. K. & Wang, W. T., 2011, Additions to the Flora of China: seven new species of Elatostema (Urticaceae) from the karst landscapes of Guangxi and Yunnan, Phytotaxa 29, pp. 1-27 : 14-17

Elatostema multicaule W.T.Wang, Y.G.Wei & A.K.Monro , sp. nov. ( Fig. 8 & 9 ).

Elatostemo asterocephalo similis sed caulibus e tubere orto, stipulis minoribus, receptalaci bractiis pistillati majoribus corniculatis, differt.

Type:— CHINA. Yunnan: Funing County, at entrance to cave with two entrances and a river flowing out of it, growing on travartine, 23°31'55.2"N 105° 44'09.2"E, 900 m, 16 May 2010, A. K . Monro & Y. G . Wei 6748 (holotype IBK, isotypes BM, MO, PE) .

Perennial herb, terrestrial, epipetric, dioecious? Tuber forming and stoloniferous, tuber ca 10 × 10 mm, grey-green. Stems 60–220 × 1.25–2.00 mm, erect to arching, subsucculent, grey, grey-green, drying finely sulcate, glabrous, internodes 9–25 mm. Stipules 2, one interpetiolar, one intrapetiolar, persistent, 1.0– 1.5 mm, ovate, glabrous. Leaves distichous, alternate, subsequent leaves subequal, subsessile, petioles 0.5–1.5 × 0.75 mm, glabrous; laminae 23–65 × 10–24 mm, length:width ratio 1:2.3–2.7, asymmetrically elliptic or obovate, weakly falcate, subchartaceous, 3-nerved, the secondary nerves 2 or 3 pairs, 30° to the midrib; upper surface drying dark dull green, glabrous, cystoliths densely scattered, fusiform, dark, ca 0.75 mm; lower surface drying dull green-brown, glabrous, cystoliths absent but imprint of upper surface cystoliths visible; base asymmetrical, obliquely cuneate; margins serrate, basal ≤1/3 entire, the teeth spaced 2.5–4.0 mm apart; apex acuminate to subacuminate. Pistillate inflorescences not borne on specialized branches, staminate inflorescences not seen. Pistillate inflorescence solitary, 3–4 mm, bearing 60–120 flowers in a pedunculate or subsessile receptacle; peduncle 1.0–1.8 × 0.75 mm, glabrous, bracteate; bract, 0.375 mm, subulate; receptacle 1.5–2.0 × 4.5–6.0 mm, suborbicular, trapeziform to rectangular, not divided into lobes or weakly divided into 2 lobes, glabrous, pale brown-green above, dull green and cream, pale green and cream below, subtended by marginal bracts, the bracts unequal, pubescent, pale green or green-brown, major bracts 2, 3 mm, 7 or 8 corniculate cuneiform, minor bracts 5, 1.5–2.0 mm, subulate. Pistillate flowers 0.5 × 0.250 –0.375 mm at anthesis, cream, pedicellate; pedicel 0.250 –0.375 mm; bracteoles 2, equal, 1.0 mm, spathulate-linear or subulate. Infructescences as pistillate inflorescences; achene 0.500 –0.675 × 0.375 mm, narrowly ovoid, 5- ribbed, raminaceous, pale brown.

Distribution:—Funing County, Yunnan and Renzhuang Town, Jingxi County, Guangxi, S. China. The two localities are 97 km apart. Elatostema multicaule is known from a cave locality in Yunnan and monsoon rain forest on limestone karst hills in Guangxi at elevations of 650– 900 m. Where growing in caves this species is found in light levels of <5% daylight (photysthetically active radiation).

Etymology:— Elatostema multicaule is named after its habit of multiple stems arising from the base.

Additional specimen examined (paratype):— CHINA. Guangxi: Jingxi County Renzhuang, limestone hill, 22°56'05"N, 106°26'00"E, ca 650 m (coordinates and elevation taken from Google Earth), 4 May 2009 Y. G . Wei 09223 ( IBK, PE) .

Discussion:— Elatostema multicaule is most similar to Elatostema asterocephalum Wang (1980) from which it can be distinguished based on leaf, stipule and pistillate inflorescence morphology as summarised in the table below:

Conservation status:—A Global Conservation Assessment is presented here based on IUCN methodology (2001, version 3.1). Elatostema multicaule is known from only two localities (criteria D2). At each locality the population of this species numbers ca 100 mature individuals (criteria D1). Plausible future threats that could drive this taxon to Critically Endangered or Extinct in a very short time are mining of the hills in which the caves are located or the use of caves in agriculture to store livestock / cultivate medicinal plants, or tourism. Using the IUCN methodology the Global Conservation Assessment for E. multicaule would be Endangered (EN) according to criteria D. We do, however, acknowledge that given the distance separating the known localities for this species that it is likely that there remain as yet undiscovered populations of this species. For this reason we downgrade the assessment to Vulnerable (VU) based on criteria D1 and D2.

Figures

FIGURE 8. Elatostema multicaule. A. Habit with tuber, stolon and pistillate inflorescences. B. Pistillate receptacle viewed from below. C. Pistillate bracteoles. D. Achene. Monro & Wei 6748, IBK (Illustration by Sun Ying-Bao and Ruth Harker).

FIGURE 9. Elatostema multicaule. A. Habitat with habit. B. Habit and leaves with pistillate infructescences. C. Base of plant with young shoots. D. Pistillate infructescence viewed from above, achenes visible. E. Pistillate inflorescence viewed from the side, major and minor bracts visible. Monro & Wei 6748 (Photo A.K. Monro).