广西楼梯草属五新种

Five new species of Elatostema J. R. et G. Forst.(Urticaceae)from Guangxi, China

关键词:  楼梯草属, 小果楼梯草, 圆序楼梯草, 对序楼梯草, 河池楼梯草, 环江楼梯草, 荨麻科, 新种

Key words:  Elatostema, Elatostema microcarpa, Elatostema gyrocephala, Elatostema binatum, Elatostema hechiense, Elatostema huanjiangense, Urticaceae, new species

摘要:

描述了在中国广西发现的楼梯草属五新种:小果楼梯草(Elatostema microcarpum W. T. Wang & Y. G. Wei)在体态方面与荔波楼梯草(E. liboense W. T. Wang)极为相似,但茎较低矮,不具软鳞片,叶上面无毛,钟乳体较小而可区别。圆序楼梯草(E. gyrocephalum W. T. Wang & Y. G. Wei)在体态上与浅齿楼梯草(E. crenatum W. T. Wang)相似,但叶两面均有糙伏毛,侧脉较少,4～6对,钟乳体较小,长约0.1 mm而不同。对序楼梯草(E. binatum W. T. Wang & Y. G. Wei)在亲缘关系方面与深绿楼梯草(E. atroviride W. T. Wang)相近,但茎和叶无毛,雄花序托较小,近方形,长度及宽度约6.5 mm,小苞片较小,长约1.5 mm,无毛,可以区别。河池楼梯草(E. hechiense W. T. Wang & Y. G. Wei)似华南楼梯草(E. balansae Gagnep.)但叶的渐尖头全缘,钟乳体较小,长0.1～0.15 mm,雌花序苞片顶端无角状突起,可以区别。环江楼梯草(E. huanjiangense W. T. Wang & Y. G. Wei)可能与樟叶楼梯草(E. petelotii Gagnep.)有亲缘关系,但后者的叶全缘,钟乳体较大,长0.3～0.7 mm,侧脉在狭侧3条,在宽侧4条,雌花序常有长花序梗,而与本种相区别。

Abstract:

Five new species of the genus Elatostema(Urticaceae)are described from Guangxi Zhuang Autonomous Region, China:(1)E. microcarpum in habit is similar to E. liboense W. T. Wang, differing in its lower unscaly stems and its leaves which are glabrous adaxially and have smaller cystoliths;(2)E. gyrocephalum in habit is similar to E. crenatum W. T. Wang, differing in its strigose leaves with fewer secondary nerves and smaller cystoliths;(3)E. binatum is related to E. atroviride W. T. Wang, differing in its glabrous stems and leaves, smaller subquadrate staminate receptacles, and smaller glabrous staminate bracteoles;(4). E. hechiense in habit is similar to E. balansae Gagnep, differing in its entire leaf acumens, smaller cystoliths of leaves, and uncorniculate pistillate bracts; and(5)E. huanjiangense is probably related to E. petelotii Gangnep, differing in its few-crenate leaves with smaller cystoliths and fewer secondary nerves and very short pistillate peduncles.