THE BOTANY OF THE KACHIN HILLS NORTH-EAS.T OF MYITKYINA. 283 
Indo-Chinese countries lying east of the Irrawaday Valley ; though 
as many as 137 of the 173 plants common to the Kachin Hills and 
the Taping Valley occur on the Shan Plateau as well, more than 
one-third of these are distributed to all parts of South-Eastern- Asia, 
and there are only four species that are peculiar to the Kachin Hills, 
the Taping Valley and the Shan Hills. 
In strong contrast with this parsimony of Chinese and of eastern 
Indo-Chinese influence in the Taping Valley flora, as represented by 
those species that this valley shares with the Kachin Hills, stands the 
fact that no fewer than i6 of these 173 species are plants that are dis- 
tinctive of the Eastern Himalaya, or of the Assam Ranges, or of both, 
and that find their eastern limit of distribution, so tar as is now known, 
in the Taping Valley. At the same time no fewer than five species 
are peculiar to the Kachin Hills and the Taping Valley, so that the 
conjoined Kachin-Taping area, though immediately bordering on 
China and the Shan Plateau, exhibits an endemic element that ex- 
ceeds numerically the Chinese and Shan elements respectively, and 
yet hardly exceeds in strength one-third the element derived from 
the more remote Himalo-Assamese areas. These facts render it 
advisable to include the Taping Valley in the natural phytogeogra- 
phical area to which the Kachin Hills proper belong, and this annexa* 
tion has the further advantage of according with the physiographi- 
cal features of the region. The Taping Valley constitutes an integral 
portion of the catchment-area of the Irrawaday, and is separated from 
the river-systems of China by the mountain-ranges that at once con- 
fine and separate the narrow gorges occupied by the Salween and the 
Mekong. 
Physiographical considerations lead equally to the suggestion 
that the Hukung Valley may also be best conjoined with the Kachin 
Hills as a preliminary measure, and an examination of the table of dis- 
tribution of our Kachin plants, where the Hukung and Taping species 
present in the Herbarium at Calcutta are indicated, bears out this 
idea. There are 34 species in the list that are known to have been ob- 
tained by Griffith in the Hukung Valley, and it is possible that still 
another Griffithii) may have come from there. Twenty of 
these species, or rather more than half, extend both westward into 
Assam, the Himalayas or India, and eastward into China, Indo-China, 
or Malaya, and thus throw no light on the affinities of the Hukung flora, 
but while there is only one that does not occur elsewhere save in the 
countries east of the Irrawaday basin, no -fewer than nine extend only 
westward, and as many as four are confined to the Irrawaday catch*- 
ment-area. Of the 13 plants that are either confined to this area or 
