SKCT. II 



PHANEROGAMIA 



603 



intrastaminal disc. Oil-containing cavities in all the members. Distributed in 

 the warmer zones of all regions. 



Important Genera. — Ruta graveolens (Fig. 606), the Rue, is a somewhat 

 shrubby plant with innnately divided leaves. The terminal floAvers of the 

 dichasial inflorescences are pentamerous in robust examples ; all the other flowers 



Fin. GOO. — Quassia anmra. (Nat. size. After Berg and Schmidt.) Official. 



are tetramerous. Didamnus FraxiiicUu has panicles of consj^icuous, dorsiventral 

 flowers ; the carpels are free in their upper portions. The important genus 

 Citrus. {*^) has peculiarly constructed flowers (Figs. 607, 608). The numerous 

 stamens are united in bundles and arranged in a single whorl. The number of 

 carpels is also increased. Tlie fruit is a berry ; the succulent portion is formed 

 of large cells with abundant cell-sap Mhich project into and fill up the loculi of 

 the ovary. The seeds have usuaPy several embryos. (Cf. p. 283.) The leaves of 

 many species are simple and provided with more or less winged petioles. Other 



