626 



ULMACEAE. 



VOL. I. 



I. 



ULMUS (Tourn.) L. Sp. PI. 225. 1753. 



Trees, with 2-ranked straight-veined inequilateral serrate leaves, with thin caducous 

 stipules. Flowers perfect or polygamous, fascicled or racemose, greenish, mostly axillary on 

 the twigs of the preceding season. Calyx campanulate, 4-Q-lobed, persistent, its lobes imbri- 

 cated. Filaments erect, slender, exserted. Ovary sessile or stalked, compressed, i-2-celled. 

 Styles 2, divergent, stigmatic along the inner margin, ovule I in each cavity of the ovary, 

 suspended, anatropous. Fruit a i-seeded flat orbicular or oval samara, its membranous 

 wings continuous all around except at the apex, commonly as broad as or broader than the 

 body. Embryo straight. [The ancient Latin name of the elm; Celtic, elm.] 



About 1 6 species, natives of the northern hemisphere. Besides the following two others occur 

 in the southern United States and one in Mexico. Type species : Ulmus campestris L. 



Flowers appearing in the spring long before the leaves. 



Leaves smooth or slightly rough above ; samara densely ciliate. 



None of the branches corky-winged ; samara-faces glabrous. i. U. americana. 



Some or all of the branches corky-winged ; samara-faces pubescent. 



Leaves 2'-$' long ; flowers racemose ; northern. 2. U. Thomasi. 



Leaves i'-3' long; flowers fascicled; southern. 3. U.alata. 



Leaves very rough above ; samara not ciliate ; twigs not corky-winged. 4. U. fulva. 



Flowers appearing in the autumn. 5. U. serotina. 



I. Ulmus americana L. American, White or 

 Water Elm. Fig. 1539. 



Ulmus americana L. Sp. PI. 226. 1753. 



A large tree, with gray flaky bark, and glabrous 

 or sparingly pubescent twigs and buds; maximum 

 height about 120, and trunk diameter 11; the 

 branches not corky-winged, terete. Leaves oval or 

 obovate, apex abruptly acuminate, base obtuse or 

 obtusish, and very inequilateral, sharply and usually 

 doubly serrate, smooth or rough above, pubescent or 

 becoming glabrous beneath, 2'-5' long, I$'-3' wide; 

 flowers fascicled ; pedicels filiform, drooping, 

 jointed ; calyx 7~9-lobed, oblique, its lobes oblong, 

 rounded ; samara ovate-oval, reticulate-veined, s"-6" 

 long, its faces glabrous, its margins densely ciliate; 

 styles strongly incurved. 



In moist soil, especially along streams, Newfoundland 

 to Manitoba, Florida and Texas. Wood hard, strong, 

 close-grained, compact, dark brown ; weight per cubic 

 foot 40.5 Ibs. March-April. Samaras ripe in May. The 

 species consists of many slightly differing races. Swamp- 

 or rock-elm. 



2. Ulmus Thomasi Sarg. Cork or Rock Elm. 

 Fig. 1540. 



Ulmus racemosa Thomas, Am. Journ. Sci. iq : 170. 18^1. 



Not Borckh. 

 Ulmus Thomasi Sargent, Silva 14 : 102. 1902. 



A large tree, attaining a maximum height of 

 about 100 and a trunk diameter of 4, the young 

 twigs puberulent; bud-scales ciliate and somewhat 

 pubescent; branches, or some of them, winged by 

 narrow plates of cork. Leaves similar to the pre- 

 ceding, but less sharply serrate, smooth above; 

 flowers racemose; pedicels filiform, drooping, 

 jointed; calyx-lobes oblong, rounded; samara oval, 

 6"-8" long, its faces pubescent or puberulent, its 

 margins densely ciliate ; persistent styles strongly 

 incurved and overlapping. 



In rich soil, Quebec to Ontario, Minnesota, Kentucky, 

 Missouri and Nebraska. Wood hard, strong, tough, com- 

 pact ; color light reddish-brown ; weight per cubic foot 45 

 Ibs. April. Called also Cliff-, hickory- or swamp-elm. 

 Racemed or corky white-elm. Wahoo. 



Ulmus campestris L., from Europe, distinguished by its nearly sessile flowers, nearly or quite 

 glabrous, not ciliate samaras, and wingless branches, rarely escapes from cultivation. 



