290 SYSTEMATIC BOTAXY. 



small, purplish, pedicellate, in lateral clusters, appearing before the leaves ; 

 fruit oval, fringed with dense down. April. 



2. U. FULVA (Slippery Elm}. Young branches rough-pubescent ; leaves 

 oblong-ovate, acute, doubly serrate ; buds covered with a rust-colored down ; 

 flowers nearly sessile, in dense clusters ; calyx hairy ; fruit nearly orbicular, 

 naked on the margin. 



6. Celtis. Flowers monoecious-polygamous. Calyx 5-6-parted, 

 persistent. Stamens 5-6. Stigmas 2, long, recurved. Drupe globu- 

 lar, i-seeded. Trees or shrubs. 



C. OCCIDENTALIS (ffackberry). Leaves ovate, entire, oblique at base, 

 rough, often cordate at base ; flowers small, greenish white, axillary, pe- 

 dunculate, appearing at the same time as the leaves ; fruit globular, with a 

 thin, sweet flesh, small, dull red. May. 



Order LXXV. JUGLANDACE^E ( Walnut Family). 



Trees. Leaves unequally pinnate. Stipules none. Flowers 

 greenish, monoecious. Sterile ones in aments. Calyx membra- 

 nous, irregular. Stamens indefinite. Fertile flowers usually in 

 small clusters. Calyx-tube adherent to the ovary ; limb 3-5- 

 parted. Petals sometimes present, and as many as the calyx-seg- 

 ments. Ovary i-celled, partially 2-4-celled, i-ovuled. Fruit dru- 

 paceous, the epicarp sometimes indehiscent, sometimes regularly 

 dehiscent ; endocarp bony. Seeds single, oily, often edible. 



( Husk 4-valved Carya. 

 JUGLANDACE^EX 



( Husk not 4-valved Juglans. 



I. Juglans. Barren flowers in long and simple aments ; stamens 

 8-40, with very short filaments. Fertile flowers solitary, or several to- 

 gether ; calyx 4-parted ; corolla 4-petaled ; stigmas 2. Fruit drupa- 

 ceous, with a spongy, indehiscent epicarp, and irregularly-furrowed 

 endocarp. Trees. 



1. J. CINEREA (Butternut). Leaves is-ig-foliate ; leaflets oblong-lance- 

 olate, serrate, obtuse at base, acuminate, pubescent ; fruit oblong, about 2' 

 in length, clothed with a clammy pubescence, tapering to an obtuse point ; 

 nut rough, with sharp, ragged ridges. April-May. 



2. J. NIGRA (Black Walnut). Leaflets numerous, 15-21, ovate-lanceo- 

 late, long-acuminate, serrate, somewhat pubescent beneath ; fruit globose, 

 covered with rough dots ; nuts marked with rough ridges. May. 



2. Carya. Barren flowers in slender aments ; calyx 3-parted ; 

 stamens 3-8, nearly destitute of filaments. Fertile flowers 2-3 togeth- 

 er ; calyx 4-parted ; corolla none ; stigma 4-lobed. Fruit globular, 

 inclosed in a 4-valved epicarp, which opens. Nut smooth, 4-6-angled, 

 Trees. 



