中国楼梯草属研究随记

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)

中国楼梯草属研究随记

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)

1)描述了自广西发现的荨麻科楼梯草属二新种，毛托叶楼梯草和弄岗楼梯草，并分别给出二种与近缘种的区别特征；(2)首次记录少齿楼梯草在中国的分布；(3)首次给出短梗楼梯草和少齿楼梯草的雌头状花序、雌花和瘦果的形态描述；(4)对楼梯草属所特有的具肋瘦果的出现时间问题进行了简略讨论。

荨麻科；楼梯草属；新种；变种；新记录；补充描述；具肋瘦果

楼梯草属ElatostemaJ.R. & G.Forster。疏伞楼梯草组短梗楼梯草系Sect. Pellionioides W.T.Wang ser. Brevipedunculata W.T.Wang。

1 短梗楼梯草 图1：A～D

ElatostemabrevipedunculataW.T.Wang in Bull.Bot.Lab.N.-E.Forest.Inst.7:22.1980;并于中国植物志23(2):211.1995;李锡文于云南植物志7:261,图版65:1.1997;Q.Lin et al. in Fl.China 5:133. 2003;W.T.Wang in Fu et al.Paper Collection of W.T.Wang 2:1070.2012;王文采,中国楼梯草属植物39,图版1:A-B.2014.Type:云南：腾冲，1964-05-21，武素功6783(♂,holotype,KUN)；镇康，1936-03，王启无72164(♂,paratype,PE).

Supplementary description to the original one, with the pistillate capitula, pistillate flower and achenes described for the first time.: Pistillate capitula singly axillary; peduncle robust, ca. 1 mm long, glabrous; receptacle either rectangular, ca. 2 mm×1.6 mm, or subquadrate, ca. 1.8 mm×1.8 mm, glabrous, deeply 2-lobed; involucral bracts ca. 21, 2-seriate, membranous, inner bract 1, semi-orbicular, ca. 0.5 mm×0.8 mm, subglabrous, outer bracts ca. 20, above dark-green, below whitish, triangular or narrowly ovate, rarely deltoid, 0.6 mm-0.8 mm×0.3 mm-0.7 mm, densely puberulous; bracteoles numerous, dense, membranous, below whitish, above brown and long ciliate, linear, 0.6 mm-1 mm×0.1 mm-0.2 mm. Pistillate flower: Pedicel robust, 0.5 mm-0.7 mm long, glabrous; tepals wanting; ovary obovoid, ca. 0.4 mm long, glabrous; stigma penicillate, ca. 0.1 mm long. Achenes whitish, ellipsoidal, ca. 0.55 mm×0.35 mm, longitudinally 6-ribbed.

地理分布：特产云南西部。

标本登录：云南(Yunnan)：保山市，芒宽乡，百花岭(Baoshan Shi,Mangkuan Xiang,Baihualing),alt.1 517 m,2012-07-23,刘杰，罗亚皇，谭少林(J.Liu,Y.H.Luo & S.L.Tan)GLGE 12246(♀,KUN.PE);同地(same locality),alt.2 426 m,2013-03-21,刘杰，罗亚皇，刘学文，杨志光，洪和斌，整飘其(J.Liu,Y.H.Luo,X.W.Liu,Z.G.Yang,H.B.Hong & P.Q.Zheng)GLGE 13623(♂,KUN,PE).

本种的二号模式标本均为具雄聚伞花序的雄株，因此在原始形态描述中缺少雌花序、雌花和果实的描述。昆明植物研究所刘杰博士于2012年在云南保山市芒宽乡山区采集到本种的雌株标本，这才能在本文中写出上述器官的补充描述。本种的雌花序具花序托和总苞，是典型的有限头状花序(determinate capitulum)[1](图1B)，这种构造复杂的花序与本种雄株具有的2～4回分枝的雄聚伞花序[2]截然不同。更值得注意的是雌花，本种的雌花发生了强烈退化，花被片全部消失，只剩下一个单独的雌蕊(图1C)，这与本种具5枚椭圆形花被片和5枚雄蕊的雄花[2]又是截然不同。同一种的雄、雌花序和雄、雌花的构造出现如此巨大的区别，是被子植物中的一个罕见现象。本种的叶具半离基三出脉，说明本种是楼梯草属原始群疏伞楼梯草组(Sect.Pellionioides)的原始种之一。本种和疏伞楼梯草组另一原始种疏伞楼梯草(E.laxicymosumW.T.Wang)的果实均具纵肋，均属于楼梯草属所独有的具肋瘦果(ribbed achene)类型(荨麻科其他所有属均无这种类型的瘦果)，这个事实支持了笔者在2014年提出的一个关于具肋瘦果的论断，即具纵肋类型的瘦果在楼梯草属自冷水花属演化而出之后不久就很快出现了[2]。

小叶楼梯草组渐尖楼梯草系Sect. Weddellia(H.schröter) W.T.Wang ser. Acuminata W.T.Wang。

2 少齿楼梯草(变种) 图1：E～H

ElatostemalineolatumWight var.integrifoliumHook. f., Fl. Brit Ind. 5: 565. 1888; Grierson & Long, Fl. Bhutan 1(1): 119. 1983. Type: no type specimen designated.

E.cuspidatumauct. non Wight: Wight, Icon. Pl. Ind. Or. 6: t. 2091, Fig.1. 1853.

Supplementary description to original one, with the pistillate capitula, pistillate flower and achene described for the first time: Pistillate capitula in pairs axillary, shortly pedunculate; peduncle ca. 2 mm long, glabrous; receptacle broadly rectangular, ca. 4 mm×2 mm, glabrous, 2-lobed; involucral bracts ca. 25, triangular-linear or linear, 1 mm-1.4 mm×0.25 mm-0.5 mm, strigillose; bracteoles numerous, membranous, whitish, cuneate-linear or linear, ca. 1 mm long, above longitudinally brown-lineolate, apex ciliate. Pistillate flower shortly pedicellate: tepals 4, narrowly ovate, ca. 0.2 mm long, glabrous, longitudinally brown-lineolate; ovary narrowly ellipsoidal, ca. 0.4 mm long, glabrous; stigma penicillate, 0.15-0.3 mm long. Achenes whitish, ellipsoidal, ca. 0.6 mm long, longitudinally 4-ribbed and sparsely minutely tuberculate.

Herbs ca. 45 cm tall(according to the field notes). Stem glabrous. Leaves alternate, shortly petiolate or sessile; blades papery, oblanceolate or narrowly obovate, (4-)8-16 cm×(1-)2-4.6 cm, apex cuspidate or acuminate, base obliquely cuneate, margin near apex with a few teeth; surfaces both adaxially and abaxially glabrous, or abaxially on midrib sparsely puberulous; nervation semi-triplinerved, with secondary nerves 2-3 at leaf narrow side and 4-5 at broad side; cystoliths dense, conspicuous, bacilliform, 0.15-0.4 mm long; petioles 0-3 mm long, glabrous; stipules membranous,greenish-white, linear-lanceolate, ca. 14 mm×2-2.8 mm, glabrous, longitudinally 1-nerved.

地理分布：尼泊尔、不丹、印度北部和东北部，在我国西藏首次记录。

标本登录：西藏(Xizang)：聂拉木县，樟木镇(Nielamu Xian,Zhangmu Zhen),alt.1 750 m,常绿阔叶林(in evergreen broad-leaved forest)，草本高30～45 cm(herbs 30-45 cm tall),2012-07-03,高连明，严丽君，吴之坤(L.M.Gao,L.J.Yan & Z.K.Wu)GLM-123661(KUN,PE).

本变种与在我国南部广布的狭叶楼梯草(E.lineolatumWight var.majusWedd.)的区别在于本变种的茎无毛，叶片中脉的二级脉较少，在叶狭侧2～3条，在宽侧4～5条，雌头状花序总苞苞片条形，被短糙伏毛，瘦果的纵肋4条。在狭叶楼梯草，茎的枝条密被糙伏毛，叶狭侧和宽侧的中脉二级脉均多达8条，雌头状花序总苞苞片三角形，被开展缘毛，瘦果的纵肋7条[2]。

本变种的原始描述非常简略，只给出了叶的描述[3]，因此，在本文中根据上列采自西藏樟木的雌株标本写出了本变种营养和生殖器官的形态描述。

骤尖楼梯草组骤尖楼梯草系(Sect.Elatostemaser. Cuspidata W.T.Wang)。

3 毛托叶楼梯草 图2：A～E

ElatostemavillosistipulumW.T.Wang, sp. nov. Holotype:广西(Gangxi)：巴马县，坡月(Bama Xian,Poyue)，alt. 300 m，石灰岩山山洞(in a cave of a limestone hill)，草本高40 cm，叶和茎绿色，雌花序淡绿色(herbs 40 cm tall;leaves and stems green; pistillate inflorescences greenish),2009-03-03，韦毅刚(Y.G.Wei)6478(PE)。

Species nova haec est fortasse affinisE.caudatoacuminatoW.T.Wang, quod caulibus glabris, foliis utrinque glabris trinervibus, stipulis glabris vel sparse ciliolatis 1-viridi-nervibus haud lineolatis et cystolithis carentibus, bracteis involucralibus pistillatis paucioribus sex inaequimagnis duabus majoribus sublunulatis quatuor minoribus late ovatis, flore pistillato tepalis quatuor praedito differt.

Perennial herbs. Stem ca. 40 cm tall, below ca. 3.5 mm across, densely strigose, branched. Leaves alternate, shortly petiolate or sessile; blades chartaceous, obliquely oblong or narrowly elliptic, 8-13 cm×2.2-3.4 cm, apex long acuminate(acumen with margin denticulate), base obliquely cuneate or at leaf narrow side obtuse, at broad side cuneate, margin at leaf narrow side above the middle inconspicuously denticulate, at broad side above base denticulate; surfaces adaxially sparsely strigillose, abaxially on basal nerves villous and on secondary nerves strigillose; nervaton semi-triplinerved, with secondary nerves 3 at leaf narrow side and 4 at broad side; cystoliths dense, conspicuous, bacilliform, 0.1-0.35 mm long; petioles 0-2.5 mm long; stipules membranous, whitish, linear-triangular or narrowly lanceolate, 9-15 mm×2-3 mm, adaxially glabrous, on margin long ciliate, abaxially villous, densely longitudinally brown-lineolate, nerveless and with dense bacilliform cystoliths. Staminate capitula and staminate flowers unknown. Pistillate capitula singly axillary; peduncle ca. 1 mm long, puberulous; receptacle subquadrate, ca. 2.6 mm×2.2 mm, glabrous, with dense fusiform cystoliths 0.1-0.2 mm long; involucral bracts ca. 18, membranous, whitish, deltoid, 0.6-0.8 mm×0.8-1 mm, 1-green-nerved, densely ciliate; bracteoles numerous, dense, membranous, hyaline, linear, 0.9-1.2 mm×0.1-0.2 mm, above densely long ciliate. Pistillate flower: Pedicel robust, ca. 1.5 mm long, glabrous; tepals wanting; ovary ellipsoidal, ca. 0.3 mm long, glabrous; stigma penicillate, as long as ovary.

本变种在亲缘关系方面可能接近长渐尖楼梯草(ElatostemacaudatoacuminatumW.T.Wang)，与后者的区别在于本种的茎被糙伏毛，叶上面疏被短糙伏毛，下面在基出脉上被长柔毛，在二级脉上被短糙伏毛，具半离基三出脉，托叶上面无毛，下面被长柔毛，无脉，具密集纵列的褐色短线纹和密集的杆状钟乳体，雌头状花序的苞片较多，约18枚，近等大，正三角形，雌花无花被片。在长渐尖楼梯草，茎无毛，叶两面无毛，具三出脉，托叶无毛或有稀疏短缘毛，具1条绿色脉，无短线纹，无钟乳体，雌头状花序的苞片较少，6枚，不等大，2枚较大，近新月形，4枚较小，宽卵形，雌花具4枚花被片[2]。

骤尖楼梯草组麻栗坡楼梯草系Sect. Elatostema ser. Malipoensia W.T.Wang & Zeng Y.Wu

4 弄岗楼梯草 图2：F～J

ElatostemalonggangenseW.T.Wang, sp. nov.Holotype：广西(Gnagxi)：龙州县，弄岗自然保护区(Longzhou Xian,Longgang nature reserve)，alt. 180～370 m，花绿色(fls. green)，2008-10-11，中植联广西队(Guangxi Exped. Inst. Bot.)3672(PE)。

Species nova haec est affinisE.malipoensiW. T. Wang & Zeng Y. Wu, quod foliis margine denticulatis glabris, stipulis minoribus subulatis vel anguste triangularibus 1-2 mm longis glabris, capituli pistillati bracteis ivolucralibus pluribus ca. septuaginta quinque, floris pistillati stigmate penicillato recedit.

Perennial herbs. Stem ca. 30 cm tall, at the middle ca. 2 mm across, near apex hirtellous, elsewhere glabrous, longitudinally ca. 5-sulcate. Leaves alternate, shortly petiolate or sessile; blades thinly papery, obliquely oblong, narrowly obovate or long elliptic, (3-)11-20 cm×(1.2-)4-7.5 cm, apex acuminate, base obliquely cuneate, margin dentate;surfaces adaxially and abaxially strigillose; nervation penninerved, with secondary nerves 3-4 at leaf narrow side and 5-6 at broad side; cystoliths not dense, thinly bacilliform, 0.1-0.3 mm long; petioles 0-2 mm long, glabrous; stipules membranous, lanceolate or linear-lanceolate, 3-5 mm×0.6 mm, adaxially glabrous, abaxially hirtellous and with some cystoliths. Staminate capitula and staminate flowers unknown. Pistillate capitula singly axillary, pedunculate; peduncle ca. 7 mm long, glabrous; receptacle papilionaceous, ca. 18 mm×12 mm, glabrous, from peduncle apex with 4 radiate nerves; involucral bracts ca. 14, membranous, whitish, depressed-ovate, 0.5-0.7 mm×1.5-3 mm, sparsely ciliolate, apex 1-corniculate, with horn-like projections 1.5-2.2 mm long and glabrous; bracteoles numerous, dense, nearly hyaline, linear, 0.8-3 mm×0.1-0.3 mm, long ciliate. Pistillate flower: Pedicel robust, ca. 0.2 mm long, glabrous; tepals wanting; ovary narrowly obovoid, ca. 0.5 mm long, glabrous; stigma subglobose, ca. 0.05 mm in diam., glabrous. Achenes white, ellipsoidal, ca. 0.8 mm×0.5 mm, tuberculate.

图2 A～E.毛托叶楼草：A.雌茎顶部：B.托页(背面)：C.雌头状花序(下面观)：D.2苞片：E.3小苞片和雌花 F～J.弄岗楼梯草：F.雌茎顶部；G.雌头状花序(下面观)；H.2苞片和约10小苞片：I.2小苞片和雌花：J.瘦果Fig.2 A-E.Elatostema villosistipulum: A.Apical part of pistillate stem; B.Stipule,abaxial view; C.Pistillate capitulum,seen from beneath; D.Two bracts; E.Three bracteoles and pistillate flower(from holotype) F-J. E.longgangense: F.Apical part of pistillate stem; G. Pistillate capitulum,seen from beneath; H.Two bracts and ca. ten bracteoles; I.Two bractsoles and pistillate flower; J.Achene(from holotype)

本种与麻栗坡楼梯草(ElatostemamalipoenseW.T.Wang & Zeng Y.Wu)在亲缘关系上相近，与后者的区别在于本种的叶边缘具牙齿，两面均被短糙伏毛，托叶较大，披针形或条状披针形，长3～5 mm，背面被短硬毛，雌头状花序的苞片较少，14枚，雌花的柱头近球形。在麻栗坡楼梯草，叶边缘具小牙齿，无毛，托叶较小，钻形或狭三角形，长1～2 mm，无毛，雌头状花序的苞片较多，约75枚，雌花的柱头画笔头状[2]。

致谢深切感谢吴增源，刘杰二博士惠赠荨麻科珍贵标本，深切感谢钟小红女士打印本文稿件。

1.王文采.关于一些植物学术语的中译等问题(三)[J].广西植物，2009，29(1)：1-6.

2.王文采.中国楼梯草属植物[M].青岛：青岛出版社，2014.

3.Hooker J D.Elatostema[M].//Hooker J D.The flora of British India.London:L. Reeve，1875：562-574.

NotesonthegenusElatostema(Urticaceae)ofChina

WANG Wen-Tsai

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

(1)Two species of the genusElatostema(Urticaceae),E.villosistipulumandE.longgangense, are described as new from Guangxi Autonomous Rejion, and the diagnostic differences between them and their allies are given respectively; (2)E.lineolatumvar.integrifoliumis newly recorded to the flora of China; (3)The descriptions of pistillate capitula, pistillate flower and achene ofE.brevipedunculatumandE.lineolatumvar.integrifoliumare given for the first time; (4)The time of occurrence of the ribbed achenes peculiar to the genusElatostemais briefly discussed.

Urticaceae;Elatostema;new species;variety;new record;supplementary description;ribbed achene

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。

2015-03-12

Q949.737.5

A

10.7525/j.issn.1673-5102.2016.05.001