in Scduiii ampk'xicaulc. 409 



under Sempervivu/n by Sibthorj) and Lagascu from its generally 

 having eight pistils, and designated by the former as Semp. 

 tenuifolium, and by the latter as Semp. niioiiia/um. A. P. DeCan- 

 dolle has given a very good iigure of it in the seeoud of his ' Me- 

 moires p. serv. ;\ I'llist. du Regne Veget./ in plate 7. In this plant 

 the new shoots destined for the reproduction arc very nuieh 

 thickened at their apex for about an inch in length, and at the 

 same time the leaves in this place are very close together, while 

 those on the lower portion of the shoot are very few and widely se- 

 jiarate. About the time of the solstice, when the ])lant has finished 

 tiowering and formed its fruit, a com])lete arrest occurs in the 

 growth of the ])lant. Not only the main body which had flowered 

 dies away, but likewise the shorter or longer latc^ral branches, the 

 thickened apices of which constitute the newly-formed living 

 shoots. If one of these shoots be examined at this time, we find, 

 wholly inclosed by the dried sheath-like lower portions of the 

 leaves, a cyliiulrical mass of cellular tissue, the cells of which con- 

 tain niunerous starch-granules. Its axis is occupied by a small cir- 

 cle of fibres and vessels. At the apex is observed a bud consisting 

 of several inci})ient leaves, and on the surface some impressions in 

 regular order which the dried leaves have left behind where they 

 fell off. In fact, it is a true tuber which has formed above the 

 ground by the growing together of the lower parts of numerous 

 densely-crowded leaves. 



In this state of rest and of apparent want of life the plant re- 

 mains until the middle of .Vugust, at which time new leaves are de- 

 veloped from the apex of the shoot; aud one, or several rootlets from 

 the lower extremity, which soon become long and much ramified. 

 The new leaves which clothe the stem of the future year, which 

 terminates in a flower, are cylindrical, or rather seniieylindrical, 

 with a slightly acute termination, and provided at the base with a 

 small appendage as in Sedum rejlcxum, acre, and other s])ecies ; 

 they do not possess the sheath-like inferior portion which cha- 

 racterizes those by which the new tubers are enveloped ; these 

 latter are therefore formed only in the early part of the summer, 

 and no longer in the later like the others. Consequently, what 

 renders the formation of new shoots for the vegetation of the suc- 

 ceeding year remarkable, is, on the one hand, that they assume 

 the shape of tubers which are formed within peculiar sheath-like 

 leaves, which soon dry but never fall off like the others, and serve 

 as a case for the tuber during its period of rest ; on the other hand, 

 that the vital connexion of this tuber with the mother-plant 

 ceases as soon as it has become developed. 



The various authors who have described the Sedum amplexicaule 

 have noticed this kind of reproduction only briefly and with few 

 words. Sibthorp (Prodr Fl. Gr?ec. i. 355) and Lagasca (Elench. 



Ann.^ Mag. N. Hist. Vol.xv. 2¥ 



