402 



EXOGENOUS OR DICOTYLEDONOUS PLANTS. 



twice as many as the petals. Carpels two or more, borne on the 

 convex or elevated receptacle, either united or separate ; in the lat- 

 ter case the styles usually cohere when young. Seeds one or two 

 in each cell or carpel, with a smooth and shining crustaceous tes- 

 ta, albuminous, embryo rather large, straight. Ex. Zanthoxylum 

 (Prickly Ash) is the type of this order, of chiefly American, and 



nearly all tropical, plants. They are aromatic, pungent, stimulant, 

 and bitter ; these properties chiefly resident in the bark. 



756. Ord, Oclmacese is a small group, nearly allied to the last, 

 but with simple dotless leaves, not aromatic, and endowed with 

 purely bitter qualities (Ex. Castela, in Texas). Some plants of the 

 family have a scale on the inner side of each filament, as in Zygo- 

 phyllacesB, and make a near approach to Simarubaceee.* 



* ORD. SIMARUBACEJE, composed of a few tropical, and chiefly Amer- 

 ican, trees and shrubs, is of some importance in medicine. The wood 

 abounds in an excessively bitter extractive principle, called Quassine. The 

 Quassia-wood of the shops is derived from the Quassia amara of Surinam and 



FIG. 639. A flowering branch of Zanthoxylum Americanum (the Northern Prickly Ash). 

 640. A piece of a leaf, to show the pellucid dots. 6-11. Staminate flower. 642. A pistillate 

 flower, the sepals spread open. 643. Two of the pistils ; one of them divided vertically to show 

 the ovules. 644. A branch in fruit. 645. One of the dehiscent pods, and the seed. 646. Ver- 

 tical section of an unripe pod and seed ; the latter pendent from a descending funiculus, show 

 ing a slender embryo in copious albumen. 



