西藏荨麻科二新种

王文采

(中国科学院植物研究所，系统与进化植物学国家重点实验室，北京 100093)

西藏荨麻科二新种

王文采

(中国科学院植物研究所，系统与进化植物学国家重点实验室，北京 100093)

描述了自西藏发现的荨麻科二新种，亚东冷水花和定结楼梯草，并分别给出二种与近缘种的区别特征。

荨麻科；亚东冷水花；定结楼梯草；新种；西藏

图1 A～D.亚东冷水花：A.植株全形，B.雌聚散花序，C.雌花，D.瘦果和宿存花被 E～I.定结楼梯草：E.植株全形，F.叶片边缘一部分，示三角形缘毛，G.雄头状花序，H.另一较小雄头状花序，I.小苞片Fig.1 A-D.Pilea yadongensis：A. Habit, B. Pistillate cyme, C. Pistillate flower, D. Achene with persistent perianth(from holotype) E-I. Elatostema dingjieense：E. Habit, F. Part ot margin of leaf blade,showing trinangular cilia, G. Staminate capitulum, H. Another smaller capitulum, I. Bracteoles(from holotype)

亚东冷水花 图1：A～G

PileayadongensisW. T. Wang，sp. nov. Fig.1: A-D

(Sect.UrticellaMig. set.CavalerianaeC. J. Chen)

Ob herbas humiles glabras, cymas pistillatas longe pedunculatas species nova haec est fortasse affinisP.clarkeiHook f. e descr., quae foliis oblongo-ovatis vel lanceolatis, stipulis late ovatis obtusis differt.

Small annual herbs. Stems slender, 8-15 cm tall, below ca. 1 mm across, glabrous, shortly branched. Leaves opposite, petiolate, glabrous, those of the same pair slightly unequal in size; blades thinly papery, broadly ovate, orbicular-ovate or ovate, (0.2-)0.6-1.8 cm×(0.2-)0.4-1.8 cm, apex obtuse, rounded or acute, base rounded, broadly cuneate or emarginate, margin at each side 1-5-denticulate, or entire; nervation trinerved, with a pair of inconspicuous lateral nerves; cystoliths dense, conspicuous, bacilliform, 0.1-0.25 mm long; petioles slender, 0.1-1.6 cm long; stipules narrowly triangular, ca. 0.8 mm long, apex acute. Staminate cymes unknown. Pistillate cymes in pair or singly axillary, glabrous; peduncles slender, 0.3-2 cm long, apex with dense flowers, or at apex dichotomously branched and at branch apexes with dense flowers; bracts linear, ca. 0.5 mm long. Pistillate flower shortly pedicellate or sessile: tepals 3, strongly unequal in size, glabrous, the dorsal one largest, green, navicular-oblong, ca. 0.5 mm long, with a few cystoliths, abaxially below apex with a papillose projection, the other two whitish, lanceolate-linear, ca. 0.25 mm long; pistil slightly shorter than dorsal tepal, ovary narrowly ovoid, ca. 0.4 mm long, glabrous, stigma penicillate, ca. 0.05 mm long. Achenes whitish-yellowish, biconvex, long ovate, ca. 1 mm long, smooth.

西藏自治区(Xizang Autonomous Region)：亚东县，自康布至亚东途中(Yadong County,on the way from Kangbu to Yadong), alt. 3 310-3 600 m,山坡林缘(at forest margin on slope),2010-08-25,PE西藏队(Xizang Expedition from PE)1795(holotype,PE),1818(paratype,PE).

本种为低矮小草本，无毛，雌聚伞花序具长花序梗，在这些特征方面与克氏冷水花(PileaclarkeiHook f.)相似，可能有亲缘关系，与后者的区别：本种的叶呈宽卵形或圆卵形，托叶呈狭三角形，顶端急尖。在克氏冷水花，叶呈长圆状卵形或披针形，托叶宽卵形，顶端钝[3]。

定结楼梯草 图1：E～I

ElatostemadingjieenseW. T. Wang, sp. nov. Fig.1: E-I

[Sect.Weddellia(H. Schröter) W. T. Wang ser. Monandra W. T. Wang]

Ob folia trinervia, capitula staminata receptaculis inconspicuis praedita, bracteas staminatas 2-seriatas species nova haec est similisE.duyunensiW. T. Wang & Y. G. Wei, quod foliorum laminis minoribus usque ad 4.5 cm longis et 1.6 cm latis margine in quoque latere 3-4-denticulatis et ciliis filiformibus haud hyalinis obtectis, capitulis staminatis binatim axillaribus breviter pedunculatis, bracteis staminatis duabus externis omnibus apice 1-corniculatis haud crestatis recedit.

Perennial herbs. Stems ca. 16 cm tall, near base 1-1.5 mm across, glabrous or above near nodes with a few short hairs, simple or from below long 2-3-branched. Leaves alternate, sessile or subsessile; blades thinly papery, obliquely oblong or elliptic, 1-7 cm×0.5-2.4 cm, apex long to shortly acuminate, base at leaf narrow side cuneate, at broad side auriculate or rounded, margin at each leaf side 5-10-dentate and with cilia hyaline narrowly triangular, ca. 0.2 mm long, abaxially on basal nerves sparsely hirtellous or glabrous; nervation trinerved, with lateral nerves 1 at leaf narrow side and 2 at broad side; cystoliths not dense, inconspicuous, bacilliform, 0.2-0.4 mm long; stipules membranous, whitish, linear, 3-5.5 mm×0.2-0.4 mm, glabrous, longitudinally 1-nerved. Staminate capitula singly axillary, sessile, 2-4 mm long, 3-5-flowered; receptacles inconspicuous; bracts 4-6, 2-seriate, membranous, glabrous, outer bracts 2, opposite, navicular-oblong, ca. 2.5 mm×1.2 mm, in one of the two, abaxially below apex long or thickly 1-corniculate, and in another one, abaxially below apex longitudinally 1-crested, inner bracts 2-4, oblong-obovate, at apex slightly cucullate and shortly 1-corniculate, or broadly oblong, at apex truncate-rounded and shortly 1-corniculate, not cucullate, ca. 2 mm×1 mm; bracteoles 7-16, dense, linear or cuneate-linear, 1.2-1.8 mm×0.2-0.7 mm, at apex subtruncate and erose, glabrous or on apex with 1-2 short hairs. Staminate flower buds subglobose, ca. 1 mm in diam., glabrous, at apex shortly 1-2-corniculate. Pistillate capitula unknown.

西藏自治区(Xizang Autonomous Region):定结县，陈塘镇，嘎玛沟(Dinggyê County,Chentang Town,Gama Valley), alt. 2 426 m，林下(under forest)，草本，花绿色(herbs, with green fowers),2013-07-13,PE西藏队(Xizang Expedition from PE)3219(holotype,PE:isotypes,two sheets,PE).

本种的叶具三出脉，雄头状花序具不明显的花序托，雄苞片排成2层，在这些特征方面与都匀楼梯草(ElatostemaduyunenseW.T.Wang & Y.G.Wei)相似，与后者的区别在于本种的叶片较大，长达7 cm，宽达2.4 cm，边缘每侧具5～10枚牙齿和狭三角形透明的短缘毛，雄头状花序单生叶腋，无花序梗，2外层苞片的一枚苞片在背面顶端之下具1角状突起,另一枚苞片在背面具1鸡冠状突起。在都匀楼梯草，叶片较小，长达4.5 cm，宽达1.6 cm，边缘每侧具3～4枚小牙齿和丝形不透明缘毛，雄头状花序成对腋生，具短花序梗，2外层雄苞片均在顶端具1条角状突起，不具鸡冠状突起[1]。

致谢深切感谢孙英宝先生为本文绘图。

1.王文采.中国楼梯草属植物[M].青岛：青岛出版社，2014.

2.Chen C J，Monro A K.Pilea[M].//Wu Z Y，Raven P H.Flora of China.Beijing：Science Press，Missouri：Missouri Botanical Garden Press，2003：92-121.

3.Hooker J D.Pilea[M].//Hooker J D.The flora of British India[M].London：L.Reeve，1888：551-558.

TwoNewSpeciesofUrticaceaefromXizang

WANG Wen-Tsai

(State Key Laboratory of Systematic and Evolutionary Botany,Institute of Botany,Chinese Academy of Scienses,Beijing 100093)

Two species of the family Urticaceae,PileayadongensisandElatostemadingjieense, are described as new from Xizang Autonomous Region. The diagnostic differences between them and their allies are given respectively.

Urticaceae;Pileayadongensis;Elatostemadingjieense;new species;Xizang

王文采(1926—)，男，研究员，中国科学院院士，从事有花植物分类学研究。

2016-03-30

Q949.737.5

A

10.7525/j.issn.1673-5102.2016.05.002