180 THE FLOWER. 



middle ; Penthorum (Fig. 335, 336) has its five carpels coales- 

 cent almost to the top, and usually loses its petals by abortion ; 

 in Grammanthes and Cotyledon (Fig. 332-334), the sepals are 

 coalescent into a cup and the petals into a deeper one, out of 



which the stamens appear to arise, these being adnate to the 

 corolla. Symmetrical increase in the number of members of 

 each circle is no proper deviation from type, at least in this 

 family (in which flowers on the same plant sometimes vary from 

 5-merous to 4-merous and 6-merous) ; and in Sempervivum (to 

 which Houseleek belongs) these members are always more than 

 five and sometimes as many as twenty in each circle. 



2. REGULAR UNION OF SIMILAR PARTS. 



329. Coalescence, or the cohesion by the contiguous margins 

 of parts of the same circle or constituent set of organs, is so fre- 

 quent that few flowers are completely free from it. The last 

 preceding figures show it in the gyncecium and corolla. Fig. 

 471-476 further illustrate it in the corolla, and in various degrees 

 up to entire union ; and Fig. 483-488 illustrate it in the andros- 

 cium. The technical terms which coalescence calls for, and 

 which are needful in botanical description, may be found under 

 the account of the particular organ, and in the Glossary. Such 

 growing together of contiguous members in the blossom is strictly 

 paralleled by connate-perfoliate leaves of ordinary foliage (212, 

 Fig. 215), where it more commonly occurs in upper leaves, and 

 in bracts, which are still nearer the flower. 



330. It should now be hardly necessary to explain that the 

 terms coalescence, cohesion, union, and the corresponding phrases 



FIG. 332. Flower of Grammanthes. 333. Flower of a Cotyledon. 334. The corolla 

 laid open showing the two rows of stamens inserted on It. 335. The five pistils of 

 Penthorum, united, 336. A cross-section of the same. 



