110 TRANSACTIONS OF THE [Sess. lxxxi 



elongate aerial rhizomes which are lengthening slowly, the 

 scales are short and crowded round the growing point ; 

 but in plants in vigorous growth, or in seedlings, they 

 have a greater importance, and assume instructive forms. 

 Under certain circumstances, too, such as exuberant 

 growth, or when the rhizome is cut off below the surface 

 of the ground, slender subterranean sucker-like branches 

 of the root-stock are produced, whose behaviour after 

 reaching the surface deserves attention. 



Fig. 8 represents one season's growth of a vigorous aerial 

 shoot of the root-stock of S. f astir/ latum, H. f. et T., a typical 

 Himalaj^an dioecious, tetramerous-flowered Rhodiola : for 

 clearness, the leafy flower-shoots have been cut away. 

 The form of the scales is seen clearly here, and it is to be 

 noted that the younger ones are prolonged into a blunt 

 linear tip, which is green and leaf-like. A further stage 

 in the development of the scales is seen in fig. 9, which 

 represents the upper part of a sucker-like shoot arising 

 from a Toot-stock cut ofl" below ground of S. himalense, D. 

 Don, another dioecious, tetramerous-flowered Rhodiola from 

 the same region. Here the scales are quite leaf -like, and 

 form a small rosette, their broad clasping bases being pro- 

 longed upwards into green oblong laminae (fig. 10), which 

 in texture and colour resemble the leaves of the flower- 

 shoots. The subterranean lower scales are distant, colour- 

 less, and thin, with axillary buds which give rise to 

 branches of the sucker ; the axils of the upper aerial leaf- 

 like scales in the following season produce flower-shoots. 



Let us next take S. crassipes, one of the Rhodiolas with 

 hermaphrodite 5-parted flowers and an elongate root-stock, 

 widely spread in the Himalayan region. Fig. 11 shows a 

 sucker similar to that last referred to, but rather older. 

 Here the scales have the usual clasping base, and a well- 

 developed lanceolate slightly toothed lamina (fig. 12) ; they 

 are, in every sense, leaves. From their axils flower-shoots 

 are seen rising. Below ground the scale-leaves are small ; 

 and at the apex of the shoot they have already passed 

 beyond the leafy stage, and have adopted the crowded 

 habit and reduced size found in the mature plant, the 

 lamina having shrunk to a mere flat green tip. 



The seedling forms of S. crassipes show an analogous 



