西藏蕁麻科二新種

王文采

(中國科學院植物研究所，系統(tǒng)與進化植物學國家重點實驗室，北京 100093)

西藏蕁麻科二新種

王文采

(中國科學院植物研究所，系統(tǒng)與進化植物學國家重點實驗室，北京 100093)

描述了自西藏發(fā)現(xiàn)的蕁麻科二新種，亞東冷水花和定結(jié)樓梯草，并分別給出二種與近緣種的區(qū)別特征。

蕁麻科；亞東冷水花；定結(jié)樓梯草；新種；西藏

圖1 A～D.亞東冷水花：A.植株全形，B.雌聚散花序，C.雌花，D.瘦果和宿存花被 E～I.定結(jié)樓梯草：E.植株全形，F(xiàn).葉片邊緣一部分，示三角形緣毛，G.雄頭狀花序，H.另一較小雄頭狀花序，I.小苞片F(xiàn)ig.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)

亞東冷水花 圖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.

西藏自治區(qū)(Xizang Autonomous Region)：亞東縣，自康布至亞東途中(Yadong County,on the way from Kangbu to Yadong), alt. 3 310-3 600 m,山坡林緣(at forest margin on slope),2010-08-25,PE西藏隊(Xizang Expedition from PE)1795(holotype,PE),1818(paratype,PE).

本種為低矮小草本，無毛，雌聚傘花序具長花序梗，在這些特征方面與克氏冷水花(PileaclarkeiHook f.)相似，可能有親緣關(guān)系，與后者的區(qū)別：本種的葉呈寬卵形或圓卵形，托葉呈狹三角形，頂端急尖。在克氏冷水花，葉呈長圓狀卵形或披針形，托葉寬卵形，頂端鈍[3]。

定結(jié)樓梯草 圖1：E～I

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

[Sect.Weddellia(H. Schr?ter) 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.

西藏自治區(qū)(Xizang Autonomous Region):定結(jié)縣，陳塘鎮(zhèn)，嘎瑪溝(Dinggyê County,Chentang Town,Gama Valley), alt. 2 426 m，林下(under forest)，草本，花綠色(herbs, with green fowers),2013-07-13,PE西藏隊(Xizang Expedition from PE)3219(holotype,PE:isotypes,two sheets,PE).

本種的葉具三出脈，雄頭狀花序具不明顯的花序托，雄苞片排成2層，在這些特征方面與都勻樓梯草(ElatostemaduyunenseW.T.Wang & Y.G.Wei)相似，與后者的區(qū)別在于本種的葉片較大，長達7 cm，寬達2.4 cm，邊緣每側(cè)具5～10枚牙齒和狹三角形透明的短緣毛，雄頭狀花序單生葉腋，無花序梗，2外層苞片的一枚苞片在背面頂端之下具1角狀突起,另一枚苞片在背面具1雞冠狀突起。在都勻樓梯草，葉片較小，長達4.5 cm，寬達1.6 cm，邊緣每側(cè)具3～4枚小牙齒和絲形不透明緣毛，雄頭狀花序成對腋生，具短花序梗，2外層雄苞片均在頂端具1條角狀突起，不具雞冠狀突起[1]。

致謝深切感謝孫英寶先生為本文繪圖。

1.王文采.中國樓梯草屬植物[M].青島：青島出版社，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，研究員，中國科學院院士，從事有花植物分類學研究。

2016-03-30

Q949.737.5

A

10.7525/j.issn.1673-5102.2016.05.002