376 The New York ^^tate College of Forestry 



mens as many as tlie petals or twice as many, distinct; filaments with a scali^ 

 or hairs at tlie base, inserted luider the disk; anthers 2-celled, introrse; pistil 

 consisting of a 2-5-celled ovary terminated by a like number of styles. Fruit 

 a drupe or samara. 



TRKE OF HEAVEN. Genus AILANTHUS Desf. 



Trees or shrubs with pale bitter bark, pinnate leaves, greenish 

 white flowers and samaroid fruit. The genus contains seven or 

 eight species, all natives of eastern Asia, the East Indies and 

 Australia. Ailanthus glandulosa Desf. has become widely natural- 

 ized about cities and tOA^Tis in eastern United States. 



Leaves alternate, petioled, deciduous, odd-pinnately compound, consisting 

 of numerous, somewhat oblique, ovate or ovate-lanceolate sub-entire leaflets. 

 Flowers small, polygamous, greenish white, borne in large terminal panicles; 

 calyx short, 5-cleft; petals 5, spreading, valvate; disk henusi)heric, 10-lobed; 

 staminate flowers ill-scented, with ten stamens; fertile flowers with 2-3 abor- 

 tive or functional stamens; pistil consisting of a deeply 2-5-lobed ovary 

 surmounted by a like number of united styles. Fruit a linear-oblong samara 

 with membranous veiny wing surrounding the 1-seeded seminal cavity; 

 samaras generally clustered, 



SUMACH FAMILY. ANACARDIACEAE 



Trees, shrubs or vines with acrid resinous or milky juice, pithy 

 branchlets, alternate simple or compound leaves, generally polyga- 

 mous flowers, and drupaceous fruit. A large family comprising 

 about fifty genera and some four hundred species, natives of 

 tropical or the milder portions of the temperate zones. 



Leaves alternate, simple or pinnate, estipulate. Flowers regular, minute, 

 dioecious or polygamous; calyx-lobes generally 5; petals of the same number 

 or wanting; stamens of the same number as the petals or twice as many 

 and inserted ^ith them on the edge of an annular disk; filaments filiform; 

 anthers oblong, 2-celled, longitudinally dehiscent; pistil consisting of a 

 1-celled, 1-ovuled ovary terminated by 1-3 styles and stigmas. Fruit a small 

 drupe; seed exalbuminous ; cotyledons fleshy. 



THE SUMACHS. Genus RHUS L, 



The genus Rhus includes more than a hundred species of trees, 

 shrubs, and climbing vines, chiefly natives of the milder portions 

 of the north and south temperate zones, So.me are extremely 

 poisonous ; others are important as sources of tannin material, 

 waxes and gums, and as ornamental plants. Sixteen or seventeen 

 species are indigenous to the United States and are scattered from 

 coast to coast. Five of these become small trees. 



