RUTACEAE 



HoPTREE. Wafer-ash 

 Ptelea trifoliata L. 



HABIT. An unarmed shrub or small tree 20-25 feet high and 

 6-8 inches in diameter; crown round-topped. 



LEAVES. Alternate or rarely opposite; compound with 

 3 (rarely 5) subsessile, ovate to oblong leaflets; acuminate at 

 apex; entire or crenulate-serrate margins; becoming glabrous 

 and rather leathery; dark green above, pale and dotted with 

 transparent glands below; deciduous; long-petioled. 



FLOWERS. Regular; polygamous; in terminal cymes or 

 compound umbels; on pubescent pedicels; calyx 4— 5-parted, 

 pubescent; corolla green-white; 4-5 petaled; stamens 3-4. 



FRUIT. Dehiscent samara; 2-3-celled; broad, thin, almost 

 orbicular wing, nearly 1 inch across; in drooping clusters on 

 slender pedicels; persisting on branches through winter. Seed: 

 Yi inch long, oblong, acute, dark red-brown. 



TWIGS. Slender; round; pubescent at first, becoming glabrous, 

 dark brown, lustrous and marked by wartlike excrescences and 

 conspicuous leaf scars. Winter buds: terminal absent; lateral 

 small, depressed, pale, tomentose. 



BARK. Smooth; thin; bitter; ill-scented; dark brown on old 

 trunks; that of the roots sometimes used as a tonic. 



WOOD. Rather heavy; hard; close-grained; ring-porous; 

 heartwood yellow-brown; sapwood thin; unimportant. 



SILVICAL CHARACTERS. Rather tolerant and often an 

 "understory" tree; dry, rocky soils. 



GENERAL. The western form ranging from Texas to Colorado, 

 Utah, and California is known as narrowleaf hoptree, P. august- 

 ifolia Benth. 



* * * 



Hercules-club. Prickly-ash 

 Zanthoxylum clava-herculis L. 



A distinctive small tree with peculiar conical, corky growths 

 I inch or more in diameter on the smooth gray bark; leaves 

 alternate, late-deciduous, pinnately compound with 7-19 

 leathery, ovate, toothed leaflets; dioecious, clustered flowers; 

 an ovoid, brown, wrinkled capsule |4 inch long, with the single 

 black seed hanging from it at maturity; and spiny twigs. The 

 common prickly-ash, Z. americanum Mill., ranges widely through 

 eastern North America and while commonly a shrub, has been 

 reported as a small tree. 



[285] 



