GERANIALES. 



541 



Ailanthus glandulosus, the Tree of Heaven, a native of China, is com- 

 monly planted in the United States as a shade tree. Its wood is valu- 

 able in cabinet-making. 



Order Butaceas. The Rue Family. Shrubs and trees, rarely herbs, 

 with glandular-punctate heavy-scented foliage ; leaves generally com- 

 pound and alternate ; stamens generally distinct. The order as here 

 considered includes 650 known species, widely distributed in tropical 



FIGS. 503-505. ILLUSTRATIONS OP CITRUS AURJLNTIUM. 



FIG. 503. 



FIG. 504. FIG. 505. 



Fig. 502. Section of flower. Magnified. 

 Fig. 503. Part of andrcecium. Magnified. 

 Fig. 504. Flower diagram. 

 Fig. 505. Calyx and ovary. Magnified. 



and temperate climates. Seven tribes, most of which were former!/ 

 considered to be orders, are recognized by Bentham and Hooker. 



Tribe Aurantiece, with actinomorphic, monoclinous flowers, 

 baccate (berry-like) fruits, and seeds without endosperm. (Figs. 502-5.) 



Citrus Aurant'um, the Sweet Orange, is an Indian tree, now grown 

 throughout all warm countries of the world for its well-known fruits. 



C. Limonum, the Lemon, is a native of Northern India, now widely 

 distributed. It was introduced into Europe during the Crusades. 



Other species of Citrus yield valuable fruits, as C. medica, the Citron ; 

 C. Limetta, the Lime ; C. decumana, the Shaddock ; (7. Bigaradia, the 

 Seville or Bitter Orange, etc., etc. 



The hard yellow wood of the Orange is valued for inlaying 



