94 Bulletin of tlie University of Texas 



ULMACEAE Mirbel. The Elm Family. 



Trees with watery juice; leaves alternate, simple, serrate, 

 pinnately veined; flowers small and without the corolla; fruit 



a, samara, drupe or small nut. 



Leaves with one primary vein at base, lateral veins 



parallel. 

 Fruit a samara winged all the way around. ... 1. Ulmus. 



Fruit a small nut with soft tubercles 2. Planera. 



Leaves 3-veined at the base, fruit a fleshy, juicy 



drupe 3. Celtis. 



1. ULMUS L. The Elms. 



Trees with deeply furrowed bark; leaves simple, alternate 

 two ranked, doubly serrate, taper pointed, unequal at base, 

 lateral veins prominent and parallel; flowers small clustered 

 appearing in the spring before the leaves in all except one 

 species; fruit a samara surrounded by a wide membranous 

 wing. 



Flowers opening in the autumn, borne in the axils 



of the leaves of the season 1. U. crassifola. 



Flowers opening in the spring before the leaves. 



Branches corky winged 2. U. alata. 



Branches not corky winged. 



Leaves smooth or somewhat roughened 



above, inner bark not mucilaginous. . . 3. U. Americana. 

 Leaves very rough above inner bark, 



mucilaginous '. 4. U. fulva. 



1. Ulmus crassifolia Nuttall. Cedar Elm. A forest tree 

 sometimes reaching a height of 80 with trunk diameter of 

 2-3, but usually smaller. The branches are usually wide- 

 spread and droop, forming a flat topped wide crown. Leaves 

 oblong-oval with rounded apex and unequal base, finely 

 doubly serrate, very rough and dark green above with soft 

 pubescence below, l'-2' long, %'-!' wide. The flowers ap- 

 pear in the autumn in the axils of the season's leaves. They 

 are borne in clusters of three to five. The fruit ripens in 

 September or sometimes in November, depending upon the 

 time of flowering. The bark is light brown, tinged with red, 



