60 FOUNDATIONS OF BOTANY 



1. U. americana, L. WHITE ELM. A large tree with gray bark, 

 drooping branches, and smooth or slightly downy twigs. Leaves 

 oval or obovate, abruptly taper-pointed at the apex, obtuse and 

 oblique at the base, slightly rough above, soft downy or soon smooth 

 beneath. Flowers in close fascicles, peduncles slender, smooth. 

 Fruit oval or obovate, with 2 sharp teeth bending toward each 

 other at the apex, wing reticulate-veined, downy on the margin. 

 In moist, rich soil. A widely planted ornamental tree; wood 

 strong but warping badly, and not durable when exposed.* 



2. U. alata, Michx. WINGED ELM. A small tree with branches 

 corky-winged. Leaves small, ovate-lanceolate, acute, sharply serrate, 

 base nearly equal-sided, rough above, downy beneath, nearly sessile. 

 Flowers in small clusters. Fruit oblong, downy on the sides, ciliate 

 on the edges. On rich soil. Occasionally producing a second set of 

 flowers and fruit from September to November.* 



3. U. fulva, Michx. SLIPPERY ELM. A tree of medium size 

 with rough downy twigs, and rusty, densely woolly bud-scales. 

 Leaves large, thick, very rough above, downy beneath, ovate or 

 obovate, taper-pointed at the apex, unsymmetrical, obtuse or some- 

 what cordate at the base, coarsely and doubly serrate, calyx-lobes 

 and pedicels downy. Fruit broadly oval, downy over the seed, the 

 wing smooth. Inner bark very fragrant when dried, and a popular 

 domestic remedy.* 



H. CELTIS, Tourn. 



Trees or shrubs with entire or serrate, petioled leaves. 

 Flowers greenish, axillary, on wood of the same season, the 

 staminate in small clusters, the fertile single or 2-3 together.* 



1. C. occidentalis, L. HACKBERRY. A large or medium-sized 

 tree having much the appearance of an elm, bark dark and rough. 

 Leaves ovate, taper-pointed at the apex, abruptly obtuse and inequi- 

 lateral at the base, sharply serrate, often 3-nerved from the base, 

 smooth above, usually somew T hat downy below. Fruit a small, dark 

 purple stone fruit. On rich soil. 



2. C. mississippiensis, Bosc. SOUTHERN HACKBERRY. A tree 

 usually smaller than the preceding, bark gray, often very warty. 

 Leaves broadly lanceolate or ovate, long taper-pointed at the apex, 

 obtuse or sometimes heart-shaped at the base, entire or with very 

 few serratures, smooth on both sides, 3-nerved. Fruit a purplish- 

 black, globose stone fruit.* 



