112 TRANSACTIONS OF THE [Sess. lxxxi 



part of its length. But none of these American species 

 have the broad clasping leaf- base or the thickened root- 

 stock of the Rhodiola section, and they have reached their 

 present form along some other line of descent. 



So far I have dealt only with species which I have had 

 an opportunity of studying in the growing state, because 

 these can be watched at different stages of growth, and 

 under varying conditions. Dried material is not nearly so 

 satisfactory among plants which vary so much and dry so 

 badly as the group with which we are dealing. Descrip- 

 tions are still less satisfactory : for instance, the clasping 

 leaf -base, which I believe I am right in treating as of first 

 importance, is not mentioned in the original descriptions of 

 *S^. "prhnuloides and aS*. Praegerianum. Nevertheless, further 

 points regarding the questions dealt with above may be 

 gleaned from a study of dried specimens, where available, and 

 of the descriptions of some other species — mostly recently 

 published — from the area extending from Afghanistan to 

 China. Some further evidence derived from living plants 

 is also added. Beginning at the Praegerianum end of the 

 series, three species have been described by M. Raymond 

 Hamet — S. Hobsonii,^ S. Durisij^ and S. Balfouri^ (the 

 first and third from Tibet, the second from Central Asia) — 

 which are clearly allied to *S^. Praegerianum. The descrip- 

 tions are full, and I have examined the types of the first 

 and third. In all the caudex is short, thick and erect as 

 in Praegerianum., and is similarly crowned with a rosette 

 of entire leaves, attached to the caudex by a broad clasping 

 base. In B. Balfouri these leaves are sessile, linear-obovate, 

 mucronate at the apex, very broad at the base (fig. 15). 

 They closely resemble those specially vigorous scale-leaves 

 of S. hitnalense (fig. 10) to which reference was made on a 

 previous page. The axillary flower-stems of *S'. Balfouri 

 are quite tall (over a foot), and its inflorescence and flowers 

 recall those of Praegerianum. In S. Durisi the lamina is 

 " obovato-suborbicularis," very obtuse, cuspidate ; the indis- 

 tinct petiole " latissimuni, cuneiforme, basi latum." S. Hoh- 

 sonii comes quite near *S'. Praegerianum ; the leaves are 



' Kew Bulletin, l-'if), 1913. Tyi^e at Kew. 



- Bull. Soc. Bot. France, Ix, 446, 1913. 



3 Notes Roy. Bot. Oard. YA'm., viii, 116, 1912. Type at Edinburgli. 



