114 TRANSACTIONS OF THE [Sess. lxxxi 



(fig. 19); in this species, by the end of the first year, these 

 juvenile leaves have given place to green deltoid acute 

 scales, like those of aS^. crassvpes, S. hhnalense, etc. ; a similar 

 case is shown in fig. 20, which represents the juvenile 

 caudex-leaf of a Chinese species (Ward, No. 764) not yet 

 described ; here also triangular scales soon replace the 

 petiolate leaves of the young plant. 



Compare also the long-stalked orbicular seedling-leaves 

 of S. hupleuroidfis (fig. 21). This species is one of the small- 

 scaled roseiim series ; the seedling, after producing about 

 three of these leaves ^ during the first few months of its 

 life, abruptly exchanges them for quite insignificant brown 

 scales (figs. 22, 23). 



Leaving now those species which in the mature state 

 possess caudex leaves with a petiole and distinct lamina, 

 there follows a large group, showing considerable diversity 

 of habit, leaf, and flower, but agreeing in its thick, mostly 

 elongate caudex, well - developed scales often prolonged 

 while young into a short, narrow, green lamina, and flowers 

 (as in the preceding groups), hermaphrodite and 5-parted. 

 The old scales are membranous, the old flower-stems often 

 persistent, the carpels usually slender and erect, with slender 

 erect styles. The familiar *S'. crassipes, Wall. (*S^. asiaticum, 

 Clarke nee DC.j may be taken as a type. Some twenty 

 species, which range from the Himalayas to China, may be 

 placed here. The well-known and peculiar Himalayan S. 

 trijiduin, Wall, seems to fit best with this group, although 

 in its scales it comes nearer the romum group referred to 

 below. 



We arrive now at Rhodiola sensu stricto — a group differ- 

 ing from the last in its usually 4-parted dioecious flowers, 

 with short carpels crowned with short styles which are 

 reflexed in fruit. The plants which belong here divide 

 themselves into two tolerably well-marked groups: — S. 

 himalense, D. Don and allied species on the one hand, with 

 well-developed scales resembling those of the crassipes 

 group, and old stems usually persistent ; and, on the other 

 hand, the familiar *S'. roseum, Scop, and its allies, Avith 

 poorly-developed scales and deciduous flower-stems. 



' It may be noted that the expanded Vjase of the .seedling-leaves of 

 .S'. hiipUuroides is suffused with purple, precisely as in S. primuloides. 



