楼梯草属二新种

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 )



楼梯草属二新种

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 )

该文描述了荨麻科楼梯草属2新种，其中发现自贵州的安龙楼梯草与条叶楼梯草近缘，与后者的区别在于此新种的茎和叶无毛，叶片椭圆形或狭倒卵形，较宽，雄苞片无角状突起，雌头状花序无梗，其花序托不等3～4裂，柱头画笔头状；自广西发现的厚序楼梯草与福贡楼梯草近缘，与后者的区别在于此新种的叶片质地较薄，呈膜质，上面疏被糙伏毛，叶柄较短，长达2 mm或不存在，雄花序梗圆柱形，较长，密被短柔毛，雄总苞由一层不具角状突起的苞片组成。

荨麻科， 楼梯草属， 新种， 中国

安龙楼梯草图1： A-F

Elatostema anlongense W. T. Wang, sp. nov. Fig. 1： A-F

[sect.Weddellia(H. Schröter) W. T. Wang ser.SublineariaW. T. Wang]

Species nova haec est fortasse affinisE.sublineariW. T. Wang, a quo caulibus et foliis glabris, foliorum laminis longe ellipticis vel anguste obovatis latioribus (2.8-3.4 cm latis), bracteis staminatis haud corniculatis, bracteolis staminatis glabris, capitulis pistillatis sessilibus, eorum receptaculis inaequaliter 3-4-lobatis, bracteolis pistillatis glabris, stigmatibus penicillatis recedit. InE.sublineari, caules et folia pubescentia, foliorum laminae anguste oblanceolatae vel lineari-oblanceolatae 1.2-2.2 cm latae, bracteae staminatae apice corniculatae, bracteolae staminatae dense ciliatae, capitula pistillata breviter pedunculata, eorum receptacula indivisa vel 2-lobata, bracteolae pistillatae longe cilia-tae, et stigmata breviter teretia sunt.

图 1　A-F. 安龙楼梯草　A. 开花茎上部; B. 雄头状花序(侧下面观); C. 同B，侧面观; D. 雄小苞片和雄花蕾； E. 雌头状花序(下面观)； F. 雌小苞片和雌花。G-N. 厚序楼梯草　G. 2叶和一腋生雄头状花序以及一对腋生雌头状花序; H. 雌头状花序(下面观); I. 外层雌苞片和5内层雌苞片; J. 雌小苞片和雌花; K. 瘦果; L. 雄头状花序(下面观); M. 3雄苞片; N. 雄小苞片和雄花蕾。Fig. 1　A-F. Elatostema anlongense　A. Upper part of flowering stem; B. Staminate capitulum, seen from the lateral bottom; C. The same as B, seen from one side; D. Staminate bracteole and staminate flower bud; E. Piatillate capitulum, seen from beneath; F. Pistillate bracteoles and pistillate flower. (from holotpye)　G-N. E. pachycephalum　G. Two leaves and an axillary staminate capitulum and a pair of axillary pistillate caputula; H. Pistillate caputulum, seen from beneath; I. One outer pistillate bract and five inner pistillate bracts; J. Pistillate bracteoles and pistillate flower; K. Achene; L. Staminate capitulum, seen from beneath; M. Three staminate bracts; N. Staminate bracteoles and staminate flower bud. (from holotype)

Perennial herb, monoecious. Stem ca. 36 cm tall, near base 2 mm in diam., glabrous, simple, ca. 7-leaved. Leaves alternate, sessile or shortly petiolate, glabrous; blades papery, obliquely long elliptic or narrowly obovate, 6-9.6 × 2.8-3.4 cm, apex acuminate, base obliquely cuneate, margin denticulate; nervation pinnate, with 5-6 pairs of inconspicuous secondary nerves; cystoliths not dense, bacilliform, 0.1-0.3 mm long; petioles 0-1 mm long; stipules white, membranous, narrowly triangular, 7-9 × 3-4 mm, 1-nerved. Staminate capitula singly axillary, pedunculate; peduncle white, ca. 3 mm long, glabrous; receptacle small, subquadrate, ca. 2 mm long, glabrous; bracts ca. 7, white, membranous, broadly triangular or broadly ovate, 1-2 × 1.2-2 mm, subglabrous; bracteoles ca. 10, white, membranous, semi-hyaline, linear, 2.5-3 × 0.3-0.4 mm, glabrous. Staminate flower: Pedicel white, 0.4-1.5 mm long, glabrous. Staminate flower bud subglobose, ca. 1.2 mm in diam., tetramerous, glabrous, near apex brown-puncticulate. Pistillate capitula singly axillary, sessile; receptacle subpentagonal, ca. 4 × 5 mm, glabrous, unequally 3-4-lobed; bracts ca. 40, membranous, linear or narrowly triangular, 0.8-1 × 0.2-0.3 mm, glabrous; bracteoles numerous, dense, near apex green, narrowly linear, 0.6-1 × 0.1-0.2 mm, glabrous. Pistillate flower: Pedicel ca. 0.1 mm long, glabrous. Tepals wanting. Pistil ca. 4.5 mm long; ovary ellipsoid, ca. 0.25 mm long, glabrous; stigma penicillate, with dense hairs ca. 0.2 mm long.

贵州(Guizhou)： 安龙县 (Anlong Xian),石灰岩山(in lime-stone hill), 2010-05,韦毅刚(Y. G. Wei) 6681 (Holotype, PE)。

本种在亲缘关系上可能接近条叶楼梯草(E.sublineareW. T. Wang)，与后者的区别在于本种的茎和叶均无毛，叶片长椭圆形或狭倒卵形，较宽(宽2.8～3.4 cm)，雄苞片无角状突起，雄小苞片无毛，雌头状花序无梗，其花序托不等3～4裂，雌小苞片无毛，柱头画笔头状。在条叶楼梯草，茎和叶均被柔毛，叶片狭倒披针形或条状倒披针形，宽1.2～2.2 cm，雄苞片顶端具角状突起，雄小苞片密被缘毛，雌头状花序具短梗，其花序托不分裂或2裂，雌小苞片被长缘毛，柱头短圆柱状(王文采，2014)。

厚序楼梯草图1: G-N

Elatostema pachycephalum W. T. Wang, sp. nov.

(sect.Elatostemaser.AlbopilosaW. T. Wang)

Ob folia penninervia, capitula staminata longius pedunculata et receptaculis discoideis praedita et achenia longitudinaliter 6-costata species nova haec ad sect.Elatostemaser.AlbopilosaW. T. Wang pertinet, et in serie hac est affinisE.fugongensiW. T. Wang, a quo foliorum laminis tenuioribus membranaceis supra sparse strigosis, petiolis brevioribus vel nullis usque ad 2 mm longis, pedunculis staminatis teretibus 14-26 mm longis dense puberulis, involucris staminatis ex bracteis 1-seriatis apice haud corniculatis constantibus facile differt. InE.fugongensi, foliorum laminae papyraceae supra glabrae, petioli 3-4.5 mm longi, pedunculi staminati complanati breviores 12 mm longi glabri, et involucra staminata ex bracteis 2-seriatis apice breviter crasseque cornitulatis constantia sunt.

Perennial herbs. Stems ca. 30 cm tall, near base ca. 3.5 mm in diam., glabrous, simple, ca. 8-leaved, longitudinally shallowly 4-sulcate. Leaves alternate, shortly petiolate or sessile; blades membranous, long elliptic or oblanceolate, 15-22 × 4-8 cm, apex long acuminate, base obliquely cuneate, margin obtusely denticulate; surfaces adaxially sparsely strigose, abaxially glabrous; nervation pinnate, with secondary nerves ca. 5 at leaf narrow side and 7 at broad side, and with midrib abaxially prominent; cystoliths along nerves dense, bacilliform, 0.1-0.25 mm long; petioles 0-2 mm long, glabrous; stipules not seen. Staminate capitula singly arising from axils of apical leaves; penduncle white, terete, 14-26 mm long, ca. 3 mm in diam., densely puberulous (haires ca. 0.1 mm long); receptacle subquadrate, ca. 10 × 10 mm, sparsely puberulous; bracts ca. 20, white, membranous, broadly ovate, ca. 1 mm long, abaxially 1-green-ribbed; bracteoles dense, membranous, linear or triangular, 0.3-0.6 × 0.1-0.3 mm, densely ciliate. Staminate flower buds numerous, subglobose, ca. 1 mm in diam., pilose, tetramerous, with glabrous pedicels 0.5-1.5 mm long. Pistillate capitula in pairs axillary; peduncle complanate, rectangular, ca. 1.5 × 2.5 mm, glabrous; receptacle thick, obliquely elliptic, ca. 5.5 × 4.5 mm, puberulous; bracts ca. 21, 2-seriate, white, membranous, outer bract 1, broadly triangular, ca. 0.5 × 1 mm, puberulous, inner bracts ca. 20, broadly triangular, deltoid or triangular, 0.4-1 × 0.5-1 mm, puberulous, ciliolate; bracteoles numerous, dense, membranous, linear, 0.3-0.6 × 0.1-0.3 mm, densely ciliate. Pistillate flower: Pedicel roubust, 0.1-0.25 mm long, glabrous. Tepals 2, linear, ca. 0.25 mm long, glabrous. Pistil ca. 0.8 mm long; ovary ovoid or narrowly ovoid, 0.3-0.5 mm long, glabrous; stigma penicillate, ca. 1.5 mm long. Achenes whitish, narrowly ellipsoid, ca. 0.7 mm long, longitudinally 6-ribbed, with ribs conspicuously prominent.

广西(Guangxi)： 那坡县，百合乡，北坎(Napo Xian, Baihe Xiang, Beikan),alt. 600 m,山谷湿处(in wet places in valley)，草本直立，花白色(herbs erect, fls. white), 2000-10-09，邓云飞等(Y. F. Deng et al.) 15544 (holotype, PE)。

本种的叶具羽状脉，雄头状花序具较长梗和盘状花序托，瘦果具6条纵肋，根据这些特征应隶属骤尖楼梯草组疏毛楼梯草系(sect.Elatostemaser.Albopilosa)，在此系中与福贡楼梯草(ElatostemafugongenseW. T. Wang)相近缘，与后者的区别在于本种的叶片质地较薄，呈膜质，上面疏被糙伏毛，叶柄较短或不存在，存在时长达2 mm，雄花序梗圆柱形，长14～26 mm，密被短柔毛，雄总苞由一层不具角状突起的苞片组成。在福贡楼梯草，叶片纸质，上面无毛，叶柄长3～4.5 mm，雄花序梗扁平，较短，长12 mm，无毛，雄总苞由2层苞片组成，苞片顶端具短而粗的角状突起(王文采，2014)。

致谢深切感谢孙英宝先生为本文绘图。

WANG WT, 2014.Elatostema(Urticaceae) in China [M]. Qingdao: Qingdao Press. [王文采, 2014. 中国楼梯草属植物 [M]. 青岛：青岛出版社. ]

Two new species ofElatostema(Urticaceae) from China

WANG Wen-Tsai

(StateKeyLaboratoryofSystematicandEvolutionaryBotany,InstituteofBotany,ChineseAcademyofSciences， Beijing 100093, China )

Two species of the genusElatostema(Urticaceae) are described as new, of which,E.anlongensewas discovered from Guizhou Provice, and is related toE.sublineareW. T. Wang, differing from the latter in its glabrous stems and leaves, braoder long elliptic or narrowly obovate leaf blades, not corniculate staminate bracts, sessile pistillate capitula, 3-4-lobed pistillate receptacles, and penicillate stigma. The other new species,E.pachycephalumwas discovered from Guangxi Zhuang Autonomous Region, and is related toE.fugongenseW. T. Wang, differing from the latter in its thinner membranous adaxially strigose leaf blades, shorter petioles, longer terete and densely puberulous staminate penduncles, and the staminate involucres consisting of 1-seriate, not corniculate bracts.

Urticaceae，Elatostema， new species， China

10.11931/guihaia.gxzw201506020

2015-06-17

2015-07-06

王文采(1926- )，男，研究员，中国科学院院士，著名植物分类学家，长期从事有花植物分类学研究。

Q949

A

1000-3142(2016)09-1019-04

王文采. 楼梯草属二新种 [J]. 广西植物， 2016， 36(9)：1019-1022

WANG WT. Two new species ofElatostema(Urticaceae) from China [J]. Guihaia， 2016， 36(9)：1019-1022