ACCOUNT OF GENUS SEDUM AS FOUND IN CULTIVATION. 127 



Habitat. — East and Central Siberia ; Mongolia. 



It is unusual among Sedums in having a double flowering period ; 

 the spring bloom is borne by a few of the strongest shoots of the 

 autumn, and a more abundant bloom appears in late summer. 

 Described as being scabrous, but this character is not apparent in my 

 plants to any appreciable degree. 



Frequent in cultivation, but often under erroneous names, such 

 as Aizoon and dentatum. The name chosen by Linnaeus for the 

 species conveys the false impression that it is a hybrid. 



SECTION VI.— MEXICANA. 



Mexicana {sectio nova). 



Perennial. Roots fibrous. Rootstock thickening horizontally, 

 or contracted. Stems tufted, erect (at least at first) , usually biennial, 

 dying to the root after flowering, the succeeding set usually arising 

 while the preceding set is flowering, so that the plants are evergreen. 

 Flowers hermaphrodite, 5-parted, mostly white, very rarely red or 

 yellow. 



Tender Mexican plants. 



Series I. Sedastrum Rose {pro genere). 



Stems (6-12 inches high) arising from Sempervivum-like basal 

 rosettes of leaves, which may continue for a year or more before they 

 shoot up to flower. Carpels hollowed behind the scales. 



A rather distinct group of soft, fleshy, often downy, Mexican plants, 

 which Rose has considered sufficiently distinct to form a genus, but 

 the only feature which they possess not found in any other Sedums 

 is the peculiar depression in the lower part of the outer face of the 

 carpel, into which the hypogonous scale is pressed. A somewhat 

 similar hollowing out to receive the scales is found in the petals of 

 S. indicum Hamet. 



glahrum no v. comb. ehracteaium M09. and Sess6. 



pachucense nov. comb. ruhricaule nov. comb. 



Hemsleanum Rose. chapalense S. Watson. 



43. Sedum glabrum nov. comb. (fig. 66). 



Synonym. — Sedastrum glabrum Rose in "N. Amer. Flora," 22, 58, 1905. 



A well-marked member of the Sedastrum group, differing from all 

 the rest in being completely glabrous throughout. The red markings 

 on its white petals are also characteristic, and very rare in the genus 

 Sedum. 



Description. — Totally glabrous, pale green, very fleshy. Rootstock soft, 

 very fleshy, spreading horizontally. Barren stems extremely short. Flower- 

 ing stems erect, round, smooth, leafy, about 8 inches long (Rose). Leaves alter- 

 nate, those of barren stems forming a lax rosette, oblong-obovate (ovate — Rose), 

 not narrowed at base, obtusely pointed at apex, flat or concave on face, much 

 rounded on back, ij inch long, nearly i inch broad, J inch thick ; those of the 



