416 



THE ROSALES 



ever (Sedum), we have a flower that has always been cited as 

 the typical flower of the angiosperms. It is very regular with 

 five whorls of alternating parts of five members each, i. e. : 5 

 sepals, 5 petals, 5 to 10 stamens (one or two whorls) and usually 

 5 pistils (Fig. 310, A). This type closely resembles the arrange- 

 ment of parts in the buttercups, save for the slight adhesion of 

 the calyx and receptacle (Fig. 310, D). These fleshy plants as 

 illustrated in the houseleek (Fig. 69), hen and chickens, etc., are 

 very common forms of xerophytes. Owing to their ability to 

 retain moisture (page 40) they can exist in the crevices of 

 rocks and upon dry soil, while the formation of roots from a bit 

 of stem or even a leaf, as well as their habit of producing buds 

 on short stems that afterward become detached and grow into 

 new plants, brings about a sure distribution and explains their 

 popular name, live-forever. 



(a) Some Variations of the Rose Order. The active growth 

 of the base of the receptacle and the consequent crowding result 



FIG. 311. Higher forms of the Rosales : A, flower of the saxifrage. B, 

 flower in section, showing the partial adhesion of receptacle to ovary. C, 

 inflorescence of currant (Ribes). D, section of flower, showing receptacle 

 forming the cavity for the ovules which is roofed over by the carpels, 

 epigynous flower. 



