RHAMNACE^E 661 



crested on the inner surface. Fruit generally solitary on a stem ^'-\' long, ' in 

 length, with thin black, flesh. 



A tree, sometimes 30 high, with a trunk 8'-10' in diameter, and very slender 

 branchlets at first green and covered with dense velvety pubescence, becoming gla- 

 brous in their second year, and then gray faintly tinged with red and roughened by 

 small crowded lenticels; generally much smaller and more often shrubby than arbo- 

 rescent. Bark of the trunk about ^' thick and divided into prominent rounded longi- 

 tudinal ridges broken on the surface into short thick light gray scales. Wood 

 exceedingly heavy, hard, strong, close-grained, brittle, rich orange-brown, with thin 

 lighter colored sap wood. 



Distribution. Florida, from Cape Canaveral on the west coast, through the 

 southern keys to the shores of Bay Biscayne; one of the commonest of the small 

 trees of the region ; also on the Bahama and West Indian islands. 



4. RHAMNUS, L. 



Trees or shrubs, with terete often spinescent branches, without terminal buds, and 

 scaly or naked axillary buds and acrid bitter bark. Leaves alternate or rarely ob- 

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

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

 fascicled cymes; calyx campanulate, 4-5-1 obed, 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 stamens, deciduous, or 0; stamens 4 or 5; filaments 

 very short; anthers oblong-ovate or sagittate, rudimentary and sterile in the pistil- 

 late flower; ovary free, ovoid, included in the tube of the calyx, 2-4-celled, rudi- 

 mentary 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 sepa- 

 rable cartilaginous 1-seeded nutlets. Seeds erect, obovate, 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 Australia 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 /ic^j/os, the classical name of the Buckthorn. 



CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES. 

 Flowers polygamo-dicecions, in sessile umbels ; calyx 4-lobed ; petals ; anthers oblong-ovate ; 

 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). 



Flowers perfect, in pedunculate umbels ; calyx 5-lobed ; petals 5 ; anthers sagittate ; lobes 

 of the stigma short and obtuse ; fruit black ; seed rounded on the back ; seed-coat mem- 

 branaceous ; leaves deciduous ; winter-buds naked. 



