THE POLYPETALOUS ORDERS. 403 



757. Ord, Aliacardiaceae (the Cashew Family). Trees or shrubs, 

 with a resinous or milky, often acrid juice, which turns blackish 

 in drying : the leaves alternate, without stipules, and not dotted. 

 Flowers small, often polygamous or dioecious. Calyx of three to 

 five sepals, united at the base. Petals, and usually the stamens, 

 as many as the sepals, inserted into the base of the calyx or into a 

 hypogynous disk. Ovary one-celled, but with three styles or stig- 

 mas, and a single ovule. Fruit a berry or drupe. Seed without 

 albumen. Embryo curved or bent. Ex. Rhus, Anacardiurn 

 (the Cashew), Pistacia. Chiefly tropical ; but several species of 

 Rhus are indigenous to the United States. The acrid resinous 

 juice is used in varnishes ; but it often contains a caustic poison. 

 Even the exhalations from Rhus Toxicodendron (Poison Oak, Poi- 

 son Ivy), and R. venenata (Poison Sumach, Poison Elder), as is 

 well known, severely affect many persons, producing erysipelatous 

 swellings, &c. Their juice is a good indelible ink for marking 

 linen. But the common Sumachs (R. typhina and R. glabra) are 

 innocuous ; their astringent bark is used for tanning ; and their 

 sour berries (which contain birnalate of lime) for acidulated drinks. 

 The oily seeds of Pistacia vera (the Pistacia-nut) are edible. The 

 drupe of Mangifera Indica (Mango) is one of the most grateful of 

 tropical fruits. The kernel of the Cashew-nut (Anacardium occi- 

 dentale) is eatable ; and so is the acid enlarged and fleshy pedun- 

 cle on which the nut rests : but the coats of the latter are filled 

 with a caustic oil, which blisters the skin ; while from the bark of 

 the tree a bland gum exudes.* 



Guiana, or more commonly, at least of late years, from Picraena excelsa of 

 Jamaica. It has been used as a substitute for hops in the manufacture of beer. 



* ORD. BURSERACE^E, including a great part of what were formerly 

 called Terebinthaceae, consists of tropical trees, with a copious resinous juice, 

 compound leaves usually marked with pellucid dots, and small, commonly 

 perfect flowers ; with valvate petals, a two- to five-celled ovary, and drupa- 

 ceous fruit. Their balsamic juice, which flows copiously when the trunk is 

 wounded, usually hardens into a resin. The Olibanum, used as a fragrant in- 

 cense, the Balm of Gilead, or Balsam of Mecca, Myrrh, and the Bdellium, are 

 derived from Arabian species of the order; the East Indian Gum Elemi, from 

 Canarium commune; Balsam of Acouchi, and similar substances, from vari- 

 ous American trees of this family. 



ORD. AMYRIDACE^E consists of a few West Indian plants, intermediate 

 as it were between Burseraceaa and Leguminosa?, and distinguished from the 

 former chiefly by their simple and solitary ovary. One species of Amyris 

 grows in Florida. Their properties are the same as the preceding; the trunks 

 abounding in a fragrant resinous juice. 



