云南西北部玉山竹属二新种

Two New Species of Yushania Keng f.(Poaceae) from Northwestern Yunnan in China

本文发表了云南西北部玉山竹属2新种:哈巴玉山竹Yushnia habaensis Yi et L.Yang和马辔簕Yushania gongshanensis Yi et L.Yang。哈巴玉山竹相似金平玉山竹Y.bojieana Yi,但秆较高大,高4 m^7m,直径1.5~2(2.5)cm,节间分枝一侧基部稍扁平或有时具1浅而短的纵凹线,纵细线棱纹较明显,实心或近实心,髓海绵状,干后较硬;箨鞘远长于节间(常长过节间1/3);小枝具叶较少,为(1)2枚~4枚;叶片较窄,宽5 mm^6.5(10)mm,次脉较少,为2对~3对,区别显著。马辔簕近似弯毛玉山竹Y.flexa Yi,区别在于秆柄较粗,直径达2 cm,节间长达2.5(3)cm;秆的节间较短,长20 cm^22(26)cm,中空;箨鞘远长于节间,背面疏生瘤基刺毛;叶鞘较短,长(1.8)2.2 cm^3.5 cm,叶片较窄,宽(5)6.5 mm^10 mm,易于区别。

In this paper two new species of Yushania Keng f. are reported from Northwestern Yunnan. Yushnia habaensis Yi et L. Yang is similar to Y. bojieana Yi, but taller culms ,4 ~ 7 m high, 1.5 ~ 2 （2.5） cm diam. , internodes complanate or short longitudinal ditch on base a side of ramification, obviously lon- gitudinal bridles, solid or subsolid, spongioplasm medullary and rigidity by drying; culm - sheaths culm sheath as long as internodes （length over 1/3 of internode ） , a few leaves ,2 ~ 4 per ultimate branch, nar- rower blade ,5 ~ 6. 5 （10） mm broad, secondary veins 2 ~ 3 paired. Yushania gongshanensis Yi et L. Yang seperates from Y. flexa Yi by rhizome neck of thicker, to 2 cm diam, internodes to 2. 5 （3） cm long; shor- ter internodes of culms ,20 ~ 22 （26） cm long, hollow, longer than internodes, back surface sparse tuber- culate setose;shorter leaf-sheath, （1.8） 2. 2 -3.5 cm,narrower blades, （5） 6. 5 ~ 10 mm wide.