656 



TREES OF NORTH AMERICA 



CONSPECTUS OF THE ARBORESCENT GENERA OF THE UNITED STATES. 



Flowers without petals, and in the species of the United States, without a calyx. 1 . Pistacia. 

 Flowers with a calyx and petals. 



Flowers usually dioecious by abortion; styles lateral, spreading; pedicels of the abor- 

 tive flowers becoming long and plumose at maturity; fruit compressed, very oblique; 

 leaves simple, deciduous. 2. Cotinus. 



Flowers mostly dioecious; styles terminal, short, united; stigma 3-lobed; fruit ovoid, 

 glabrous; leaves unequally pinnate, persistent. 3. Metopium. 



Flowers polygamo-dicecious or polygamo-moncecious; styles terminal, spreading; fruit 

 usually globose, naked or clothed with acrid hairs; leaves unequally pinnate, trifo- 

 liolate or rarely simple, deciduous or rarely persistent. 4. Rhus. 



1. PISTACIA L. 



Balsamic trees or shrubs. Leaves 3-foliolate or equally or unequally pinnate, petiolate, 

 deciduous or persistent. Flowers small, dioecious, subtended by a bract and 2 branchlets, 

 short pedicellate in panicles or racemes; calyx 1 or 2-lobed or in the pistillate flower 

 3-5-lobed, or 0; petals 0, stamens 3-5, in the pistillate flower; filaments short, their 

 base connate with the disk; anthers large; ovary subglobose or short-ovoid, rudimentary 

 or in the staminate flower; style 3-lobed, shorter than the 3 obovate-oblong or oblong 

 stigmas. Drupe ovoid, oblique, compressed; exocarpa thin; the stone bony, 1-seeded; 

 seed compressed; cotyledons thick plano-convex. 



Pistacia with eight or nine species is confined to the valley of the lower Rio Grande, 

 southern Mexico; the Canary Islands, the countries adjacent to the Mediterranean, and 

 northern and central China, with one species growing on the northern banks of the Rio 

 Grande in Texas. 



The Pistacio-nuts of commerce, the green or yellow seeds of P. vera L. are largely used 

 in confectionery, and some of the species are valued for the decoration of parks and gardens. 



Pistacia from TTKTT and d/ceo/xai, in reference to the healing properties of its resinous 

 exudations. 



1. Pistacia texana Swing. 



Leaves persistent or tardily deciduous, 9-19-foliolate, with a slightly winged rachis 

 pubescent above and a flattened narrow-winged petiole '-f in length; leaflets spatulate, 



Fig. 594 



