in Sedum amplexicaule. 409 



under Sempervivum by Sibthorp and Lagasca from its generally 

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

 tenuifolium, and by the latter as Semp. anomalum. A. P. DeCan- 

 dolle has given a very good figure of it in the second of his ' Me- 

 moires p. serv. fl FHist. du Regne Veget./ in plate 7. In this plant 

 the new shoots destined for the reproduction are very much 

 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- 

 parate. About the time of the solstice, when the plant has finished 

 flowering and formed its fruit, a complete arrest occurs in the 

 growth of the plant. Not only the main body which had flowered 

 dies away, but likewise the shorter or longer lateral 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 cylindrical mass of cellular tissue, the cells of which con- 

 tain numerous 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 incipient 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 August, at which time new leaves are de- 

 veloped from the apex of the shoot; and 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 semicylindrical, 

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

 small appendage as in Sedum refleocum, acre^ and other species ; 

 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 ofi" 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. Grsec. i. 355) and Lagasca (Elench. 



Ann. ^ Mag. N. Hist. Vol. xv. 2 F 



