Abstract
Using correlation and regression, leaves of Shan forms at Tanai, Tanghpre, Namhsan and Kutkai in Upper Burma were morphologically compard with Assam forms collected at Darrang, Tinsulkia, Jaipur, etc., and further 20 bushes of 2-years old seedlings introduced from Assam in Jannary, 1972 were morphologically measured.
High correlation was recognized between leaf-length and leaf-width of tea plants in both Upper Burma and Assam. With regard to regression, tea plants in three regions of Assam showed identical regression coefficient, while tea plants in Upper Burma showed lower regression coefficient, and then, as the leaf-length became larger, the leaf-bredth did not become so larger as compared with the plants of Assam forms.
With regard to the size of leaves, the range of variation was too large to classify Shan and Assam forms systematically. When the size of leaves were compared by regional groups in Assam regions, plants near Naga Hills had generally larger leaves, while those on terraced hill regions along Brahmaputra River had smaller leaves. This variation seemed to be due to environmental difference of grown areas, such as topographical or metiorological conditions.
With regard to 2-years old seedlings grown in the greenhouse, leaf character showed no apparent difference as compared with those of the plants grown in Upper Burma and Assam regions. Their leaf-length showed comparatively large of variation, about 11 to 19 cm, and their leaf-length and leaf-bredth showed same correlation and regression coefficent as those in Upper Burma and Assam.
According to the observation of the plant shape, there were two types, erect and branching, and the ratio of these two types was about 1: 1. We should, therefore, reconsider the establishing opinion that the Assam is a tall tree with sparce branches and the China form is a low shrub with dense branches. In fact the wild tea plants (var. sinensis) grown in Taiwan are often 15 m high and have sparse branches (Hasimoto, 1967) .
Henceforth it should be necessary to research into the relation between the environment of the grown areas and the variability of the tea plant, together with the studies on the morphological difference between China and Assam forms by statistical methods.
