1916-17.] BOTANICAL SOCIETY OF EDINBURGH 115 



The considerations put forward in the preceding pages 

 point to the definition and classification of the section 

 Rhodiola which is given below. The great variability of 

 many of the species (see Hooker and Thomson in Journ. 

 Linn. Soc. (Bot.), ii, 93-95) makes precise classification 

 difficult. Furthermore, in the case of some of the species 

 of which specimens are not available to me, the descriptions 

 are not sufficiently full to allow of their being placed with 

 certainty. I have marked with an asterisk the species 

 which I have had an opportunity^ of studying in the living 

 state ; the placing of some of the remainder must be re- 

 garded as tentative. I have put a i before one or two 

 species of the position of which I am doubtful. 



Certain species, as is to be expected in so puzzling an 

 assortment of forms as the Rhodiolas, are difficult to place, 

 because they are intermediate between two groups, or 

 boldly combine certain characters of two. Thus, 8. trijidiini 

 has the small scales and deciduous stems of the Roseae, and 

 the 5-parted hermaphrodite flowers and slender carpels of 

 the Crassirpedes. S. discolor bears short carpels and short 

 styles spreading in fruit of Roseae type in hermaphrodite 

 flowers like those of the Crassipedes. S. Smithi, in its 

 linear scales ending in a long subterete tail, links the 

 Crassipedes with »S'. Karpelesae and *S'. Levii, belonging to 

 the Primuloides series. 



Genus SEDUM. 



Section RHODIOLA. 



Caudex fleshy, crowned with leaves with a broad clasp- 

 ing base (often reduced to membranous deltoid or semi- 

 orbicular scales, or becoming so with age), from the axils 

 of which leafy flowering shoots are produced. 



Series 1. Rhodiolae sensu stricto. 



Flowers usually unisexual and -i-parted, caudex usually 

 elongate or greatly thickened. Carpels usually short and 

 crowned with short styles reflexed in fruit. 



Group 1. Roseae. — Caudex-leaves scale-like, short, mem- 

 branous, not green even when young. Old flower-stems 

 not persistent. 



