496 FLORA OF TEXAS. 



ULMUS, L. El^. 



Flowers perfect; calyx bell-shaped, 4:-9-c]eft; stamens 

 4-9, slender, exserted ; anthers extrorse; ovary 2-celled; 

 styles short; fruit 1-celled, 1-seeded, surrounded by a 

 broad membranaceous wing; embryo straight. — Trees; 

 leaves short-petioled, mostly oblique, doubly serrate, straight- 

 veined; stipules deciduous; flowers greenish or purplish, 

 clustered, appearing before the leaves. 



U. FULVA, Michx. {Slippery Elm.) Branclilets pubes- 

 cent; leaves thick, ovate-oblong, acuminate, broadly ser- 

 rate, slightly oblique at the base, very rough above, pubes- 

 cent beneath; calyx and short pedicels pubescent; /r?n*^ 

 orbicular, pubescent on the sides, smooth on the margins, 

 with the obtuse teeth erect; expanding huds rusty-tomen- 

 tose. Rich woods. February, March. — A small tree ; leaves 

 4-8' long; fruit 8"-9" wide ; inner bark very mucilaginous. 



U. A:jrERiCAXA, L. (Elm.) Branchlets and buds smooth; 

 leaves thin, obovate-oblong, or oval, oblique at the base, 

 sharply serrate, abruptly acuminate, smooth above, pubes- 

 cent, or at length smooth beneath ; j^cdiccls clustered, 

 slender, smootli, like the calyx ; /rznY oval or obovate, 

 downy on the margins, witii the sharp teeth connivent. 

 Low grounds. February and March. — A large tree, with 

 spreading branches; leaves 2'-4' long; fruit 6' long. 



U. ALATA, Michx. ( Wlialioo.) Branches corky-winged ; 

 leaves small, ovate-lanceolate, acute, sharply serrate, com- 

 monly even and rounded at the base, rough above, pubes- 

 cent beneath, nearly sessile ; flowers clustered, on slender 

 pedicels; fruit oval, downy on the margins. Rich soil. — 

 A small tree ; leaves I'-l^' long. 



PLAXERA, Gmel. Plaxer-tree. 



Floiuers polygamous, clustered; calyx bell-shaped, 4-5- 

 cleft; stamens 4-5; anthers extrorse; ovary 1-celled; 



