200 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



THE FLORA OF NORTH-WESTERN YUNNAN. 

 By George Forrest. 



[Read July 20, 1915 ; Mr. E. A. Bowles, M.A., F.L.S., in the Chair.] 



The flora of North-Western Yunnan is now admitted to be one 

 of the richest in the world, and the most likely to supply us with 

 garden novelties for many years to come. The region explored, 

 during seven or eight years' journeying in the province, is essen- 

 tially alpine, and, though shrubs do not bulk so largely as in 

 others from Central China, my collections hold a greater number 

 of herbaceous perennials admirably suited for alpine gardens. 



The formation of the ranges explored, composing the watersheds 

 of the Salween, Mekong, and Yangtze valleys, is principally limestone. 

 In the lower valley levels are clay, sandstone, and shale belts, but the 

 caps of the mountains are hard flinty lime, and on that the cream of 

 the flora is invariably found. 



Entering China from Bhamo, there is an easy ascent of 130 miles 

 to Tengyueh, where an altitude of 5,500 feet is attained. That dis- 

 trict, though geographically in the basin of the Irrawaddy, may be 

 considered as the commencement of the great Yunnan plateau which 

 descends from the Eastern Himalayas and gradually loses itself 

 in Szechwan and Yunnan. 



Around Tengyueh the country is volcanic, hot springs abound, 

 and there are numerous lava-beds, each many miles in extent, the 

 overflow of extinct volcanos. On those beds the richest flora is 

 established, but the region is almost subtropical, and there is there- 

 fore small hope of anything from the locality proving altogether 

 hardy with us here. True, there is at times as much as sixteen degrees 

 of frost registered, and occasional slight falls of snow, but during 

 the winter the atmosphere is extremely dry, and that nullifies the 

 effects of the cold. 



There are few Rhododendrons, the principal being Rhododendron 

 ciliicalyx Fr. and R. oxyphyllum Fr. R. racemosum Fr., the most 

 abundant of all species on the uplands of Yunnan, is not found so 

 far west. On the lava-beds Ilex Pernyi attains perfection, and, in 

 places, is the dominant shrub, forming considerable thickets. Indi- 

 vidual specimens have the symmetrical form of growth seen in 

 cultivation, and reach a height of 18 to 20 feet. There is con- 

 siderable variation in the form of foliage. ■ Another superb evergreen 

 shrub, found in similar situations, is Lonicera Braceiana. The foliage 

 is almost coriaceous, dark glossy green ; the flowers are produced in 



