中國樓梯草屬研究隨記

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)

中國樓梯草屬研究隨記

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)

1)描述了自廣西發(fā)現的蕁麻科樓梯草屬二新種，毛托葉樓梯草和弄崗樓梯草，并分別給出二種與近緣種的區(qū)別特征；(2)首次記錄少齒樓梯草在中國的分布；(3)首次給出短梗樓梯草和少齒樓梯草的雌頭狀花序、雌花和瘦果的形態(tài)描述；(4)對樓梯草屬所特有的具肋瘦果的出現時間問題進行了簡略討論。

蕁麻科；樓梯草屬；新種；變種；新記錄；補充描述；具肋瘦果

樓梯草屬ElatostemaJ.R. & G.Forster。疏傘樓梯草組短梗樓梯草系Sect. Pellionioides W.T.Wang ser. Brevipedunculata W.T.Wang。

1 短梗樓梯草 圖1：A～D

ElatostemabrevipedunculataW.T.Wang in Bull.Bot.Lab.N.-E.Forest.Inst.7:22.1980;并于中國植物志23(2):211.1995;李錫文于云南植物志7:261,圖版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,中國樓梯草屬植物39,圖版1:A-B.2014.Type:云南：騰沖，1964-05-21，武素功6783(♂,holotype,KUN)；鎮(zhèn)康，1936-03，王啟無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：特產云南西部。

標本登錄：云南(Yunnan)：保山市，芒寬鄉(xiāng)，百花嶺(Baoshan Shi,Mangkuan Xiang,Baihualing),alt.1 517 m,2012-07-23,劉杰，羅亞皇，譚少林(J.Liu,Y.H.Luo & S.L.Tan)GLGE 12246(♀,KUN.PE);同地(same locality),alt.2 426 m,2013-03-21,劉杰，羅亞皇，劉學文，楊志光，洪和斌，整飄其(J.Liu,Y.H.Luo,X.W.Liu,Z.G.Yang,H.B.Hong & P.Q.Zheng)GLGE 13623(♂,KUN,PE).

本種的二號模式標本均為具雄聚傘花序的雄株，因此在原始形態(tài)描述中缺少雌花序、雌花和果實的描述。昆明植物研究所劉杰博士于2012年在云南保山市芒寬鄉(xiāng)山區(qū)采集到本種的雌株標本，這才能在本文中寫出上述器官的補充描述。本種的雌花序具花序托和總苞，是典型的有限頭狀花序(determinate capitulum)[1](圖1B)，這種構造復雜的花序與本種雄株具有的2～4回分枝的雄聚傘花序[2]截然不同。更值得注意的是雌花，本種的雌花發(fā)生了強烈退化，花被片全部消失，只剩下一個單獨的雌蕊(圖1C)，這與本種具5枚橢圓形花被片和5枚雄蕊的雄花[2]又是截然不同。同一種的雄、雌花序和雄、雌花的構造出現如此巨大的區(qū)別，是被子植物中的一個罕見現象。本種的葉具半離基三出脈，說明本種是樓梯草屬原始群疏傘樓梯草組(Sect.Pellionioides)的原始種之一。本種和疏傘樓梯草組另一原始種疏傘樓梯草(E.laxicymosumW.T.Wang)的果實均具縱肋，均屬于樓梯草屬所獨有的具肋瘦果(ribbed achene)類型(蕁麻科其他所有屬均無這種類型的瘦果)，這個事實支持了筆者在2014年提出的一個關于具肋瘦果的論斷，即具縱肋類型的瘦果在樓梯草屬自冷水花屬演化而出之后不久就很快出現了[2]。

小葉樓梯草組漸尖樓梯草系Sect. Weddellia(H.schr?ter) W.T.Wang ser. Acuminata W.T.Wang。

2 少齒樓梯草(變種) 圖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：尼泊爾、不丹、印度北部和東北部，在我國西藏首次記錄。

標本登錄：西藏(Xizang)：聶拉木縣，樟木鎮(zhèn)(Nielamu Xian,Zhangmu Zhen),alt.1 750 m,常綠闊葉林(in evergreen broad-leaved forest)，草本高30～45 cm(herbs 30-45 cm tall),2012-07-03,高連明，嚴麗君，吳之坤(L.M.Gao,L.J.Yan & Z.K.Wu)GLM-123661(KUN,PE).

本變種與在我國南部廣布的狹葉樓梯草(E.lineolatumWight var.majusWedd.)的區(qū)別在于本變種的莖無毛，葉片中脈的二級脈較少，在葉狹側2～3條，在寬側4～5條，雌頭狀花序總苞苞片條形，被短糙伏毛，瘦果的縱肋4條。在狹葉樓梯草，莖的枝條密被糙伏毛，葉狹側和寬側的中脈二級脈均多達8條，雌頭狀花序總苞苞片三角形，被開展緣毛，瘦果的縱肋7條[2]。

本變種的原始描述非常簡略，只給出了葉的描述[3]，因此，在本文中根據上列采自西藏樟木的雌株標本寫出了本變種營養(yǎng)和生殖器官的形態(tài)描述。

驟尖樓梯草組驟尖樓梯草系(Sect.Elatostemaser. Cuspidata W.T.Wang)。

3 毛托葉樓梯草 圖2：A～E

ElatostemavillosistipulumW.T.Wang, sp. nov. Holotype:廣西(Gangxi)：巴馬縣，坡月(Bama Xian,Poyue)，alt. 300 m，石灰?guī)r山山洞(in a cave of a limestone hill)，草本高40 cm，葉和莖綠色，雌花序淡綠色(herbs 40 cm tall;leaves and stems green; pistillate inflorescences greenish),2009-03-03，韋毅剛(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.

本變種在親緣關系方面可能接近長漸尖樓梯草(ElatostemacaudatoacuminatumW.T.Wang)，與后者的區(qū)別在于本種的莖被糙伏毛，葉上面疏被短糙伏毛，下面在基出脈上被長柔毛，在二級脈上被短糙伏毛，具半離基三出脈，托葉上面無毛，下面被長柔毛，無脈，具密集縱列的褐色短線紋和密集的桿狀鐘乳體，雌頭狀花序的苞片較多，約18枚，近等大，正三角形，雌花無花被片。在長漸尖樓梯草，莖無毛，葉兩面無毛，具三出脈，托葉無毛或有稀疏短緣毛，具1條綠色脈，無短線紋，無鐘乳體，雌頭狀花序的苞片較少，6枚，不等大，2枚較大，近新月形，4枚較小，寬卵形，雌花具4枚花被片[2]。

驟尖樓梯草組麻栗坡樓梯草系Sect. Elatostema ser. Malipoensia W.T.Wang & Zeng Y.Wu

4 弄崗樓梯草 圖2：F～J

ElatostemalonggangenseW.T.Wang, sp. nov.Holotype：廣西(Gnagxi)：龍州縣，弄崗自然保護區(qū)(Longzhou Xian,Longgang nature reserve)，alt. 180～370 m，花綠色(fls. green)，2008-10-11，中植聯(lián)廣西隊(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.

圖2 A～E.毛托葉樓草：A.雌莖頂部：B.托頁(背面)：C.雌頭狀花序(下面觀)：D.2苞片：E.3小苞片和雌花 F～J.弄崗樓梯草：F.雌莖頂部；G.雌頭狀花序(下面觀)；H.2苞片和約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)

本種與麻栗坡樓梯草(ElatostemamalipoenseW.T.Wang & Zeng Y.Wu)在親緣關系上相近，與后者的區(qū)別在于本種的葉邊緣具牙齒，兩面均被短糙伏毛，托葉較大，披針形或條狀披針形，長3～5 mm，背面被短硬毛，雌頭狀花序的苞片較少，14枚，雌花的柱頭近球形。在麻栗坡樓梯草，葉邊緣具小牙齒，無毛，托葉較小，鉆形或狹三角形，長1～2 mm，無毛，雌頭狀花序的苞片較多，約75枚，雌花的柱頭畫筆頭狀[2]。

致謝深切感謝吳增源，劉杰二博士惠贈蕁麻科珍貴標本，深切感謝鐘小紅女士打印本文稿件。

1.王文采.關于一些植物學術語的中譯等問題(三)[J].廣西植物，2009，29(1)：1-6.

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

2015-03-12

Q949.737.5

A

10.7525/j.issn.1673-5102.2016.05.001