Morphology of leaves of cultivated varieties of the tea plant grown in Assam, India was investigated. As materials, 12 macro-morphologically different Assamica forms were selected, and they were compared with Naga type and China type.
Although the size of leaves of the cultivated varieties in Assam showed much variation, it was generally larger than that of China type.
In the leaf shape a continual variation was observed. The ratio of leaf length to leaf width varied from 2: 1 (eliptic) to 3: 1 (oblanceolate) . The leaves of Naga type and China type were oblong-shaped. The leaves of China type grown in Japan also showed much variation, and therefore, it might be difficult to classify Assam and China forms from the leaf shape.
The leaf shape of Naga type was considerably similar to that of wild tea plant grown in Taiwan. These two varieties are geographically separated, but it can be recognized that they are grown on the identical latitude.
The number of lateral veins of leaves in China forms was generally 5-10 pairs, while that of Assam varieties was 9-42 pairs. It seemed that the number of lateral veins was proportionate to leaf length. The leaf apex of Naga type and China type was apparently acuminate while that of Assam varieties was caudately acuminate or acute. The leaf base of Assam varieties was acute or obtuse, while that of Naga type and China type was cuneate. The leaf base of China type grown in Japan also showed acute or obtuse.
Above morphological investigation of leaves revealed that in the shape of leaves there was some difference between Assam and China varieties, however in other morphological characters of leaves almost any difference could not be found between them. Materials used in this investigation might be, however, Assam hybrids, and therefore, it would be necessary to investigate further on the purely indigenous Assamica variety.

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