20 MASSACHUSETTS HORTICULTURAL SOCIETY. 



Incarvillea compacia and /. grandiflora both with large, scarlet 

 flowers and Cypripedium tibeticum with its enormous pouches, 



dark red in color, arc other striking herbs. Also we have Meconop- 

 sis in half a dozen spe< ies — M. Hewrici with violet colored flowers, 

 M. punicea with dark-scarlet flowers, and .1/. integrifolia with 

 yellow flowers S inches or more across and possibly the most gorge- 

 ous alpine plant extant. 



The limit of vegetation is about 16,500 feet, a few cushion plants 

 belonging to Caryophyllaceae, Rosaceae, Cruciferae, and Com- 

 positae, with a tiny species of Primula and Meconopsis racemosa 

 being the last to give out. Above this altitude are vast moraines 

 and glaciers culminating in perpetual snows. The snow-line can- 

 not be less than 17,500 feet. This, though at first sight remarkable, 

 is easily accounted for by the dryness of the Thibetan plateau and 

 highlands to the immediate west. 



Having briefly outlined the different altitudinal zones and 

 instanced some of the more striking plants characteristic thereof, 

 it may be of interest to point out the altogether anomalous condition 

 of things obtaining in the river valleys of western China. These 

 valleys, between 4000 and 9000 feet, enjoy a much warmer climate 

 than their altitude warrants. They are all very similar being 

 narrow and shut in by steep and lofty mountains. The climate is 

 dry and the flora characteristically xerophytic. The shrubs are 

 characterized by being either spinous with very small leaves, or, 

 the leaves and young shoots are covered with dense, felt-like hairs. 

 The herbs have either tuberous roots, fleshy leaves or stems. The 

 thorn apple (Datura Stramonium), henbane (Hyoscijamus niger), 

 and Verbascum Thapsus are common roadside weeds. Artemisia 

 is the genus richest in species and individuals. From an orna- 

 mental standpoint, however, the various species of lilies are the 

 most important constituents of this river-valley flora. Thirty- 

 three species of lilies are known from China, 17 of which are peculiar, 

 and the majority are denizens of these -warm, dry, river valleys. 

 Of these we have L. Henryi, Brovmii, chlorastcr, 'leucanthemum, 

 myriophyllum, Bakcrianum, formosnm, sutchuenense, and many 

 others. 



In the valley of the Tung River, in the far west of China, an 

 American plant, the prickly pear (Opuntia Dillenii), has become 



