西藏落叶松属(Larix)植物分类学初步研究

Primary Research on Plant Taxonomy of Larch Genus(Larix) in Tibet

西藏产落叶松属红杉组植物在分类鉴定中普遍存在特征性状模糊不清的情况,本文即为厘清这类问题而作。整理西藏产落叶松属红杉组植物在志书中的学名与主要检索特征,结合野外调查图像资料与西藏高原生态研究所标本室(XZE)馆藏标本,进行比对分析归纳。1)《Flora of China》在原藏红杉类群中分立出贡布红杉。2)3种志书均选择雌球花与球果的苞鳞是否反折或明显后弯作为重要的检索特征。其它检索特征主要有:一、二年生小枝干后的颜色、球果大小、种鳞形态及颜色、苞鳞先端形态,《Flora of China》更是将短枝之长宽比及雄球花长度、形状作为重要特征性状。3)西藏产红杉组植物特征性状检视结果表明,疑似不同种同时出现在同一居群的情况十分普遍,如错那县、米林县之贡布红杉与藏红杉,亚东县之贡布红杉与怒江红杉,巴宜区之藏红杉与怒江红杉,波密县之怒江红杉与藏红杉,以及芒康县之红杉、大果红杉与怒江红杉。1)《Flora of China》将贡布红杉作为种来处理是不可靠的,无论是从分布区看还是从形态特征看,都应与藏红杉合并。2)在西藏分布的红杉组植物中,仅有喜马拉雅红杉在形态学上表现得较为清晰。而怒江红杉与藏红杉之间存在着明显的过渡。3)落叶松属红杉组之主要检索特征如苞鳞劲直与反折(或向后弯曲)、球果粗短与细长、种鳞颜色及形状、球果大小、针叶长度及两面具龙骨突情况、雄球花形状及大小、苞鳞形状以及短枝形态,均存在明显的过渡类型。

The larch that they distribute in Tibet show up plenty of vague characteristics of plant taxonomy. We shall clarify the problem in this paper. It is contrasted, analyzed and concluded by means of image data form the specimens which store in Herbarium of Tibet Plateau Ecology Res. Institute（XZE）, and sorted out their lartin names and main key characteristics in the Floras. Kongbo larch（L. kongboensis R. R. Mill） be separated out of Tibet larch（ L. griffithii J. D. Hooker） in the Flora of China. Bracts reflexed or obvious recurved is important key characteristic that it selected from three kinds of Floras. The other key characteristics are the colour of annual or biennial dry branchlets, size of cones, the form and colour of seed scales, and the form of bracts apex. It is exceptional that the FOC choose length-width ratio of short branchlets, length and form of pollen cones to serve as important characteristics. 3） The survey result manifest that it is very widespread which the different species are living at a same population in Tibet distribution, just as Kongbo larch and Tibet larch in Cona County, Kongbo larch and Nujiang larch（L. speciosa W. C. Cheng Y. W. Law） in Yadong County,Tibet larch and Nujiang larch in Bayi District,Nujiang larch and Tibet larch in Bome County,and Chinese larch（L. potaninii Batalin）, Big-cone larch（L. potaninii Batalin var. australis A. Henry ex Handel-Mazzetti） and Nujiang larch. It is unreliable that regard Kongbo larch as a real/good species from FOC, according to the distribution range or morphological characteristic, and it shoud be incorporated into Tibet larch. Among the species of larch genus in Tibet distribution ranges, Himalaya larch（L. himalaica W. C. Cheng L. K. Fu） is only legible at plant taxonomy, and there is obvious transition on morphology between Nujiang larch and Tibet larch. They are all exist that the transitional types of main key characteristics which they are bracts straight/bracts reflexed or recurved, seed cones stout/seed cones relatively slender, colour and form of seed scales, size of cones, length of leaves and keeled on both sides or not, size and form of pollen cones, form of bracts, and form of short branchlets.