80 



TREES OP THE NORTHERN UNITED STATES 



long, alternate, oblong, wavy and obscurely serrulate, nearly'smooth, 

 on slender pubescent petioles. Flowers greenish, 5-parted, solitary 

 or in umbellate clusters in the axils. Fruit berry-like, globular, 

 the size of peas, 3-seeded, black when ripe in September. A thorn- 

 less shrub or small tree, 5 to 20 ft. high. New Jersey, south and 



west. Usually a shrub except in the 



Southern States. 



3. Rhinnus Californicus,Esch. (CAL- 

 IFORNIA BUCKTHORN.) Leaves evergreen, 

 oval-oblong to elliptical, 1 to 4 in. long, 

 rather obtuse, sometimes acute, generally 

 rounded at base, serrulate or entire. Fruit 

 blackish purple, with thin pulp, % in., 2- 

 to 3-seeded. A spreading shrub, 5 to 18 ft. 

 B. Caiii&rnicus. high> without thorns ; from California. 



GENUS 21. HOViJNIA. 



Leaves alternate, deciduous, simple, oblique at base. 

 Fruit an obscurely 3-lobed, 3 -celled, 3-seeded pod in 

 dichotomous clusters, both axillary and terminal. 



HovSnia dtilcis, Thunb. Leaves long- 

 petioled, more or less ovate to cordate, 

 serrate, palmately 3-ribbed, much darker 

 on the upper surface ; both sides slightly 

 roughened with scattered hairs. Fruit 

 sweet, edible, in clusters in the axils of 

 the leaves ; seeds lens-shaped, with a ridge 

 on the inner side. Flowers white ; in July. 

 A large, broad-topped tree, introduced 

 from Japan. Hardy at Washington, but dies to the ground in the 

 Arnold Arboretum, Massachusetts. 



GENUS 22. ZIZYPHTJft. 



Leaves simple, alternate, deciduous, 3-ribbed. Flowers 

 axillary, 5-petaled. Fruit fleshy, drupe-like, containing 

 a 1- to 2-celled nut. 



Zlzyphus vulgaris, Lam. ( JUJUBE.) Leaves ovate-lanceolate, 

 obtuse, serrate, smooth, and glossy green on both sides, upper side 



