, or even
in the cultivated grounds of China, and consequently a great difference of
opinion has all along existed, as to whether tea is obtained from one,
two, or more distinct species of _Thea_. This question is getting day by
day more involved as new facts come to light; and, indeed, cultivation
seems to have altered the original character of some forms of the plant so
much, that the subject bids fair to remain an open question among European
botanists for ages to come. The two tea-plants which have been long grown
in British gardens, and universally supposed, until within the last few
years, to be the only kinds in existence, are the _Thea bohea_ and the
_Thea viridis_. The former was, until recently, very generally believed to
produce the black tea of commerce, and the latter the green tea; but
recent travelers have clearly shown that both _black_ and _green_ tea may
be, and are, obtained from the same plant. The difference is caused by the
mode of preparation; but it will be afterward seen that very important
discrepancies occur between the accounts of this operation given by
different observers. Certain it is, that the extreme caution with which
the Chinese attempt to conceal a knowledge of their peculiar arts and
manufactures from European visitors--and in none is their anxiety to do so
more strikingly evinced than in the case of the culture and preparation of
tea--tends greatly to frustrate the endeavors of the scientific traveler to
acquire accurate information on this point.

In the present state of our knowledge, it is quite impossible to say how
many species or varieties of the tea-plant are grown in China. They are
now believed to be numerous, although the two kinds to which we have
referred are those most extensively cultivated. They have long been
allowed to rank as distinct species in botanical books, and grown as such
in our greenhouses; but some acute botanists have, at various times,
suggested that they might be merely varieties of one plant. Such was the
opinion of the editor of the "Botanical Magazine," when he figured and
described the Bohea variety (t. 998). Professor Balfour ("Manual of
Botany,"