The tea plant of Takagi's variety (Assam kind) was discovered in the Assam area in India in 1823, and the cultivation of the latter became active in India and Sri Lanka thereafter, etc.
though tea was made from the leaf of the tea plant of the bush traditionally grown in China (China kind).
However, a Chinese kind such as Darjeeling is grown in various places and whether which only home or kind because hybridization of both is also advanced it cannot be specified.
It is a word "[Kuro-naru]" that indicates the tea plant of which number increased by the cuttage, a name to distinguish from the tea plant grown from the seed, and not a kind name.
They are the misuses though might explained calling the mixture kind of a Chinese kind and the Assam kind or cultivations by the grafting.
Therefore, [kuro-naru] of [kuro-naru] of a Chinese kind, [kuro-naru] of the Assam kind, and the mixture kind (hybrid) exists.
As for the Assam kind, it is said that the element that shows bitter than a Chinese kind is numerous, and the Assam kind or the mixture kind in general is cheaper.