TREES OF NORTH AMERICA 



and on the Everglade Keys, Dade County, near Cape Sable, and on the southern keys; 

 one of the commonest of the small trees of the region; on the Bahama Islands and on 

 several of the Antilles. 



Fig. 648 



4. RHAMNUS L. 



Trees or shrubs, with terete often spinescent branches, without a terminal bud, scaly 

 or naked axillary buds and acrid bitter bark. Leaves alternate or rarely obliquely 

 opposite, conduplicate in the bud, petiolate, feather- veined, entire or dentate, stipulate. 

 Flowers perfect or polygamo-dioecious, in axillary simple or compound racemes or fascicled 

 cymes; calyx campanulate, 4-5-lobed, the lobes triangular-ovate, erect or spreading, keeled 

 on the inner surface, deciduous; disk thin below, more or less thickened above; petals 5, 

 inserted on the margin of the disk, ovate, unguiculate, emarginate, infolded round the sta- 

 mens, deciduous, or 0; stamens 4 or 5; filaments very short; anthers oblong-ovoid or sagit- 

 tate, rudimentary and sterile in the pistillate flower; ovary free, ovoid, included in the tube 

 of the calyx, 2-4-celled, rudimentary in the staminate flower; styles united below, with 

 spreading stigmatic lobes or terminating in a 2-3-lobed obtuse stigma; ovule erect from the 

 base of the cell. Fruit drupaceous, oblong or spherical; flesh thick and succulent, inclosing 

 2-4 separable cartilaginous 1-seeded nutlets. Seeds erect, obovoid, grooved longitudinally 

 on the back, with a cartilaginous seed-coat, the raphe in the groove, or convex on the back, 

 with a membranaceous seed-coat, the raphe lateral next to one margin of the cotyledons; 

 embryo large, surrounded by thin fleshy albumen ; cotyledons oval, folia ceous, with revolute 

 margins, or flat and fleshy. 



Rhamnus with about sixty species is widely distributed in nearly all the temperate 

 and in many of the tropical parts of the world with the exception of Australasia and the 

 islands of the Pacific Ocean. Of the five species indigenous to the United States three 

 attain the size of small trees. The fruit and bark of Rhamnus are drastic, and yield 

 yellow and green dyes. The European Rhamnus cathartica L., the Buckthorn, has long 

 been used as a hedge plant in northern Europe, and in eastern North America, where it has 

 now become sparingly naturalized. 



The generic name is from pd/j.vos, the classical name of the Buckthorn. 



CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES. 



Flowers polygamo-direcious, in sessile umbels; calyx 4-lobed; petals 0; anthers oblong- 

 ovoid; lobes of the stigma elongated, spreading; fruit red; seed grooved on the back; 

 seed-coat cartilaginous; leaves often sharply toothed, persistent; winter-buds scaly. 



1. R. crocea (G). 



