1915-16.] BOTANICAL SOCIETY OF EDINBURGH 43 



boundary is not very distinct, but may perhaps be found 

 somewhere up in the Koko-Nor district, where the Sin-ling 

 rano-e em erodes from the tano-le of mountains at the northern 

 edge of the Tibetan plateau. It may be considered as 

 extending to the coast (actuallj- the great plains of the 

 Yellow river and the Yangtze intervene), keeping north of 

 the Yangtze, and though not a rich Primula area its flora 

 is in other respects equal to that of anj^ other region of 

 China. The Bur ma- Yunnan area comprises for our purpose 

 the three great parallel divides between the Eastern Irra- 

 waddy (or 'Nmai-hka) and the Yangtze ; but a good deal of 

 country to the east, including a large part of the provinces 

 of Szechwan and Yunnan, must be included in any compre- 

 hensive survey of the region. Though the mountains to 

 the west of the 'Nmai-hka belong to the same great system 

 of parallel divides, they, on the other hand, evidently do not 

 belong to this plant area, as I shall endeavour to show later. 

 In the following table the Primula sections are arranged 

 according to their distribution amongst the three areas 

 named, omitting those from the Tatsienlu area (Western 

 Szechwan), which, as already pointed out, belongs strictly 

 speaking to, or rather is a direct continuation of, the Burma- 

 Yunnan area. Numbers in brackets refer to the number 

 of species in the section. It is almost superfluous to remark 

 that additions and corrections innumerable, some of which 

 may easily be fatal to these arguments, will probabl}^ have 

 been made in the classification before this paper is finished 

 — some of "my own Primula finds of 19 13-1 914 are neces- 

 sarily excluded ; but as far as possible I have followed 

 Professor Balfour's classification. For the Chinese Primulas 

 this was comparatively eas}^ as I have before me Professor 

 Balfour's paper read before the Primula Conference of 1913. 

 Without the knowledge which it contained, and the inspira- 

 tion it gave, I take this opportunity of saying my paper 

 would never have been written. But for the Indian 

 Primulas it is less easy, as I am not altogether certain of 

 his classification and may have to some extent confused it 

 with the earlier classification of Sir George Watt, to which 

 I must also acknowledge mj^ indebtedness. However, I 

 have done the best I can to be consistent. 



