594 



BOTANY 



introduction of new members is determined by the spatial relations, so that differ- 

 ences in the numbers of members arc found in individuals of the same species. 

 The family is divided into a number of sub-families. 



I-',,,, ii-jo. dcnd diagrams of Roaaceae, A,8ortnudowutttM; /', /'/> i'a<ln*; <', /.'K.-K 7,,,, 

 D, Smtgnism-lia officinalis : /,', Spiraea 7i.v/'< a'-<./"'<<'. (After EICHI.KR.) 



() Spiraeeae. K5, C5, A 5 + 5 or more, Go; other numbers of members in the 

 whorl are less frequent. Carpels free or united, each containing two or more 

 ovules. Fruits usually dehiscent. Floral axis expanded as a more or less Hat disc. 

 The genus Spiraea has inflorescences bearing numerous flowers ; many species are 



FIG. 621. Rosaeeae. Three flowers cut through loiiKitutlinally to show ditt'en-nt forms of 

 the receptacle. 1, PotentUlu iMlnxti-is ; '. .llrheiitillii uli'ina: '>. /'//r* muliis. (After I-'OCKI: 

 in Xttturl. l'fan:enfamilien.) 



cultivated as ornamental shrubs (Fig. 623 E). QuiUajn Saponaria (Fig. 622), from 

 Chili, is an evergreen tree with shortly stalked, alternate, leathery leaves and 

 terminal dichasia usually consisting of three flowers. The flower has a five-toothed, 

 nectar-secreting disc projecting above the large sepals. Five of the stamens stand 

 at the projecting angles of the disc opposite the sepals : the other five are inserted 



