Trees of New Yorh- Sfaic 361 



ELM FAMILY. ULMACEAE 



Trees or slirubs with watery juice, terete branchlets, alternate 

 simple leaves, perfect or polygamous flowers, and a fruit which is 

 a samara, nut, or drupe. The family includes thirteen genera and 

 some one hundred and forty species, widely distributed through- 

 out the temperate regions of the northern hemisphere. Five 

 genera are represented within the boundaries of the United States, 

 three by arborescent forms in tiio eastern and southci-n states. 



Ijcavcs alternate, deciduoiis, simple, serrate, pinnivciiied, petiolate, inequi- 

 lateral at the base; stipules usually fugacious. Flowers small, perfect, monoe- 

 cious or })oljg-amous, clustered or the pistillate solitary; calyx-tube regular, 

 ■if-O-lobed or parted; petals lacking; stamens 4-6, exserted, with straight 

 filaments aiid longitudinally dehiscent anthers; pistil consisting of a 1-celled, 

 1-ovuled ovary surmounted by 2 styles and stigmas. Fruit a samara, drupe 

 or nut. 



KEY TO THE GENERA page 



1. Flowers perfect; fruit a samara Ulmus .361 



1. Flowers polygamo-nionoecious; fruit a drupe Celtis .362 



THE ELMS. Genus ULMUS (Tourn.) L. 



Trees or shrubs with scaly bark, alternate serrate inequilateral 

 leaves, perfect flowers, a fruit w'hich is a samara, and heavy tough 

 w^ood. Some sixteen species are known which are widely dis- 

 ti'ibuted through the subarctic and temperate regions of the 

 northern hemisphere, western North America excepted. Six 

 native species occur in the United States, all confined to regions 

 east of the Rocky Mountains, three of which extend into New York 

 State. 



Leaves alternate, deciduous, simple, simply or doubly serrate, with straight 

 secondary veins; stipules scarious, caducous. Bud-scales several. Floners 

 on twdgs of the previous season, vernal and appearing before the leaves or 

 autumnal and arising from the axils of the leaves of the season, perfect, 

 borne on bibracteolate pedicelsi in fascicles or racemes; calyx-tube campanu- 

 la te, membranaceous, 4-9-lobed; stamens 5-6, exserted, with slender filaments 

 and oblong anthers; pistil consisting of a sessile or stalked, compressed, 

 1-celled, 1-ovuled ovary surmounted by 2 divergent styles stigmatie on their 

 inner faces. Fruit a flat, ovate or oblong, often oblique, sessile or stalked, 

 1-seeded samara, subtended at the base by the renmauts of the calyx and 

 tipped with the renuiants of the styles; seed compressed, exalbuminous, in our 

 forms germinating in early summer. 



KEY TO THE SPECIES page 



1. Leaves scabrous above; flowers nearly sessile; samara naked on the margin . . . 



U. fulva 201 

 1. Leaves smooth or nearly so above; flowers on slender, drooping pedicels; fruit 

 ciliate on the margin 2 



