1916-17.] BOTANICAL SOCIETY OF EDINBURGH 223 



and the first leaves of the branchlets at ground surface 

 have the underside red. 



RIl. arboreum, Wall, and its Chinese representative RJi. 

 Delavayi, Franch. show the reddening of the juvenile leaf- 

 undersurface and then pass through a green stage. When 

 the indumentum begins to develop it appears along the 

 midrib and spreads out along the primary veins, but 

 does not at first reach the leaf-margin, so that the leaf 

 has a green border around the median grey -coloured 

 indumentum. 



Rh. argenteum. Hook. f. has a deep purple glandular 

 undersurface to the early juvenile leaves. Most commonly 

 in the seedlings which I have seen the following leaves 

 are green underneath before development of those with 

 characteristic tomentose indumentum of adpressed rosettes 

 of vesicular hairs appearing simultaneously over the whole 

 surface. In some, however, the red surface remains and 

 the indumentum appears in a blotched fashion upon the 

 surface. 



Rh. bullatuin, Franch. begins with leaves showing an 

 intensely red undersurface which is also lepidote, with 

 yellowish peltate discontiguous scales, and has a few 

 straight hair-bristles. By the sixth year the red surface 

 appears less conspicuous, being covered by a dense tomen- 

 tum of amber-brown interwoven hairs which conceals the 

 peltate scales. 



Rh. campanulatunn, Wall, supplies a typical example of 

 the red glandular undersui-face of the juvenile leaf, and 

 the tomentum appears simultaneously over the whole 

 surface, usually in the leaves of about the third year. But 

 I have seen some leaves with blotched indumentum and 

 some in an intermediate stage with a nearly green under- 

 surface. 



Rh. Cleraentinae, G. Forrest is a striking species in the 

 adult state, with its thick white indumentum on the leaf- 

 undersurface. Three-year-old seedlings show no trace of 

 it, and the leaves still have an intensely red undersurface 

 with glands and a few hair-flocks on midrib and at margin. 

 Later stages I do not know. 



Rh. dichroanthum, Diels. — Here the juvenile underleaf- 

 surface is deep red. 



