AN ANALYSIS OF THE VARIATION PATTERNS OF INFRA-AND INTER-POPULATIONS OF RHODODENDRON OVATUM
Hsu Ping-sheng, Gu De-xing
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Our previous paper has been concerned with the infraspe-cific variation of the widespread Rhododendron ovatum (Lindl.)Planch. based upon herbarium materials. We have shown that the species varies considerably in such characters as the shape of leaves, with or without an apical notch, margins of calyx-lobes glabrous or with glandular hairs, etc. The present paper deals with a quantitative analysis of the same morphological characters previously studied of a number of local populations of R. ovatum in order to shed some light on the infra-and inter-population variation patterns of the species. Population samplings were carried out during 1983-1984.The sites of populations were as follows:(1) Hangzhou, Zhe-jiang, (2) Huangshan, Anhui, (3) Lushan, Jiangxi, (4) Chong-an, Fujian, (5) Xingan, Guangxi, (6) Chongqing, Sichuan, and(7) Zhongxian, Sichuan (Fig. 1). As a result of a biometrical analysis of the histograms (Fig. 2), polygonal graphs (Fig. 3-4) and scatter diagrams (Fig. 5), we have found that:1. The depth and width of the apical notches of leaves vary at random as a whole, but the variables of Population No.6 are remarkably less than those of the other populations, and the two characters show more or less a correlation in variation. 2. The shape of calyx-lobes of Population No. 6 tends to be broadest below the middle, while those of the other populations are principally broadest in or above the middle. 3. Any of these populations shows a great variability in the amount of marginal hairs of the calyx-lobes, from entirely gla-brous to possessing very many hairs. But the gaverage amount of marginal hairs of Populations No. 5 is distinctly greater than those of the other populations. In general, there may be two trends of topoclinal variation among the populations examined, from those of the north-eas-tern sites to the south and south-western extremes with regard to (a) a general shift of the shape of calyx-lobes from ovate or broadly ovate to elliptic or obovate, and (b) the increase of average amount of marginal hairs of calyx-lobes per population.But the factors besides climate give rise to these variationaltrends deserve further study. Since R. xinganense G. L. Li and R. cvatum are morphologic-ally inseparable, the former is therefore reduced to be a synonym of the latter.