CRASSULACEJE. 



307 



characters. Its short unequal sepals are four in number, unsym- 

 metrically arranged. Its gynseceum consists of but three carpels, 



Sempervivum tectorum. 



Fig. 33S. 



Flowers. 



Fig. 339. 



Lontr. section of {lower. 



Se mperv i vti m tectoru m . 



1 IsMI 



« 



while there are five petals and ten stamens of Sedum ; and there 

 are only three narrow scales at the foot of the gynseceum. 

 Moreover, the carpels are united below fur a 

 somewhat variable distance. Each ovary con- 

 tains two descending ovules. The fruit is 

 formed of three carpels cohering below. Triac- 

 tina has branching stems bearing alternate or 

 pseudo-verticillate glabrous leaves. The flowers 

 form cymes, chiefly uniparous ; they are more 

 or less carried up on the neighbouring branches, 

 as in many species of Sedum; 



The Houseleeks 1 (Fr., Joubarbes ; figs. 338- 

 340) are Sedums with the floral symmetry of a higher number than five. 

 When, as is sometimes the case, the flower is pentamerous, the only 

 distinguishing character lies in the vegetative organs. The genus com- 

 prises herbs or rarely undershrubs, often stemless, with a rosette of 

 succulent leaves arranged in a spiral of the greatest regularity. Axillary 

 to the leaves buds are produced, often transformed into bulbels. The 

 flowers end a common axis bearing reduced leaves or bracts, and 

 form racemes or corymbs of C3 r mes or glomeruli, which are often 

 uniparous or scorpioid. The perianth is variable. In JEomum" and 



Fig. 340. 

 Diagram. 



1 Sempervivum L., Gen., n. 612.— J., Gen., 367, t. 79.— B. H., Gen., 660, n. 10 (inch : 



307. — G^rtn., Frtict., i. 341, t. 65. — Lamk., Monivm Webb, Aichryson Webb, Greenovia 



Diet., iii. 288 ; Supph, iii. 176 ; III., t. 413.— Wj.bb, Monanthes Haw., Petrophyes Webb 



DC, Prodr., iii. 411. — Spach, Suit, a Buffon, & Berth.). 

 v. 99.— Esdl., Gen., n. 4623.— Payer, Organog., ■ Webb, Phyt. Canar., i. 184, t. 28-35. The 



9 



