樓梯草屬二新種

王文采

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

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樓梯草屬二新種

王文采

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

該文描述了蕁麻科樓梯草屬2新種，其中發現自貴州的安龍樓梯草與條葉樓梯草近緣，與后者的區別在于此新種的莖和葉無毛，葉片橢圓形或狹倒卵形，較寬，雄苞片無角狀突起，雌頭狀花序無梗，其花序托不等3～4裂，柱頭畫筆頭狀；自廣西發現的厚序樓梯草與福貢樓梯草近緣，與后者的區別在于此新種的葉片質地較薄，呈膜質，上面疏被糙伏毛，葉柄較短，長達2 mm或不存在，雄花序梗圓柱形，較長，密被短柔毛，雄總苞由一層不具角狀突起的苞片組成。

蕁麻科， 樓梯草屬， 新種， 中國

安龍樓梯草圖1： A-F

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

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

圖 1　A-F. 安龍樓梯草　A. 開花莖上部; B. 雄頭狀花序(側下面觀); C. 同B，側面觀; D. 雄小苞片和雄花蕾； E. 雌頭狀花序(下面觀)； F. 雌小苞片和雌花。G-N. 厚序樓梯草　G. 2葉和一腋生雄頭狀花序以及一對腋生雌頭狀花序; H. 雌頭狀花序(下面觀); I. 外層雌苞片和5內層雌苞片; J. 雌小苞片和雌花; K. 瘦果; L. 雄頭狀花序(下面觀); 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.

貴州(Guizhou)： 安龍縣 (Anlong Xian),石灰巖山(in lime-stone hill), 2010-05,韋毅剛(Y. G. Wei) 6681 (Holotype, PE)。

本種在親緣關系上可能接近條葉樓梯草(E.sublineareW. T. Wang)，與后者的區別在于本種的莖和葉均無毛，葉片長橢圓形或狹倒卵形，較寬(寬2.8～3.4 cm)，雄苞片無角狀突起，雄小苞片無毛，雌頭狀花序無梗，其花序托不等3～4裂，雌小苞片無毛，柱頭畫筆頭狀。在條葉樓梯草，莖和葉均被柔毛，葉片狹倒披針形或條狀倒披針形，寬1.2～2.2 cm，雄苞片頂端具角狀突起，雄小苞片密被緣毛，雌頭狀花序具短梗，其花序托不分裂或2裂，雌小苞片被長緣毛，柱頭短圓柱狀(王文采，2014)。

厚序樓梯草圖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.

廣西(Guangxi)： 那坡縣，百合鄉，北坎(Napo Xian, Baihe Xiang, Beikan),alt. 600 m,山谷濕處(in wet places in valley)，草本直立，花白色(herbs erect, fls. white), 2000-10-09，鄧云飛等(Y. F. Deng et al.) 15544 (holotype, PE)。

本種的葉具羽狀脈，雄頭狀花序具較長梗和盤狀花序托，瘦果具6條縱肋，根據這些特征應隸屬驟尖樓梯草組疏毛樓梯草系(sect.Elatostemaser.Albopilosa)，在此系中與福貢樓梯草(ElatostemafugongenseW. T. Wang)相近緣，與后者的區別在于本種的葉片質地較薄，呈膜質，上面疏被糙伏毛，葉柄較短或不存在，存在時長達2 mm，雄花序梗圓柱形，長14～26 mm，密被短柔毛，雄總苞由一層不具角狀突起的苞片組成。在福貢樓梯草，葉片紙質，上面無毛，葉柄長3～4.5 mm，雄花序梗扁平，較短，長12 mm，無毛，雄總苞由2層苞片組成，苞片頂端具短而粗的角狀突起(王文采，2014)。

致謝深切感謝孫英寶先生為本文繪圖。

WANG WT, 2014.Elatostema(Urticaceae) in China [M]. Qingdao: Qingdao Press. [王文采, 2014. 中國樓梯草屬植物 [M]. 青島：青島出版社. ]

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，研究員，中國科學院院士，著名植物分類學家，長期從事有花植物分類學研究。

Q949

A

1000-3142(2016)09-1019-04

王文采. 樓梯草屬二新種 [J]. 廣西植物， 2016， 36(9)：1019-1022

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