云南楼梯草属二新种

Two new species of Elatostema(Urticaceae)from Yunnan

关键词:  荨麻科, 楼梯草属, 新种, 云南

Key words:  Urticaceae, Elatostema, new species, Yunnan

摘要:

该文描述了自云南东南部发现的荨麻科楼梯草属二新种。(1)文山楼梯草,与上林楼梯草在亲缘关系上相近,与后者的区别在于本种的茎密被短柔毛,叶片在基部斜楔形,具半离基三出脉,雌头状花序的花序托较小,长约1.2 mm,宽1 mm,不分裂,其雌苞片约12,不等大,只3枚在顶端具角状突起。(2)绿突楼梯草,与马关楼梯草近缘,与后者的区别在于茎密被反曲的柔毛和贴伏的短柔毛,雄花序较长,雄总苞的苞片6枚,排成2层,2外层苞片较大,背面具1绿色纵列龙骨状突起和4或6绿纵肋,4内层苞片较小,背面近中央有1绿色角状突起。

Abstract:

Two species of the genus Elatostema(Urticaceae)are described as new from southeastern area of Yunnan Province.(1)E. wenshanense is related E. shanglinense W. T. Wang, and from the latter differs in its densely puberulous stems, at base obliquely cuneate and semi-triplinerved leaf blades, smaller receptacle of pistillate capitulum, and its 12 bracts, which are unequal in size and only three of which are corniculate at apex.(2)E. viridicarinatum is related to E. maguanense W. T. Wang, and from the latter differs in its densely retrose-pubescent and appressed-puberulous stems, longer staminate peduncle, and in its staminate involucre, which consists of 6 2-serite bracts unequal in size, with the 2 outer ones larger abaxially longitudinally 1-green-carinate and 4-6-green-costate, and 4 inner ones smaller and abaxially 1-green-corniculate near the middle.