678 



The Buckthorns 



Its bark is thin and gray. The young twigs are green, more or less hairy, 



turning reddish brown and becoming smooth. 

 The buds are not more than 2 mm. long, 

 their scales hairy-f ringed. The leaves are 

 firm in texture, ovate to oval or nearly as 

 wide as long, sharply toothed with bristle- 

 tipped teeth, smooth or very nearly so, yeUow- 

 green, blunt, pointed, or sometimes notched at 

 the apex, blunt or narrowed at the base, 5 cm. 

 long or less; the leaf-stalks are 2 to 10 mm. 

 long. The polygamous or dioecious flowers 

 are rather numerous in small clusters in the 

 axils, and open from February to May, their 

 stalks 2 to 5 mm. long; the 4 green calyx- 

 lobes are about as long as the bell-shaped 

 calyx- tube; there are usually no petals; the 4 

 stamens of the staminate flowers are about as 

 long as the calyx-lobes, the anthers rather 

 longer than the filaments; the pistillate flowers 

 have 4 short rudimentary stamens, a 2-celled ovary with a slender style and 2 

 slender stigmas. The fruit is obovoid, red, 5 to 7 mm. long, its stalk about the 

 same length; it contains 2 grooved nutlets. 



Fig. 629. — Holly-leaved Buckthorn. 



4. PEAR-LEAVED BUCKTHORN — Rhamnus pyrifolia Greene 



Inhabiting, so far as known, only the islands off the coast of southern California, 

 this small evergreen tree sometimes 

 attains a height of 10 meters, with 

 a trunk up to 2 dm. thick, but is 

 sometimes shrubby. It has been 

 confused with Rhamnus insulus of 

 Kellogg, which is endemic on Cer- 

 ros island. Lower California. 



The bark is smooth, dark gray 

 to nearly black, the young twigs 

 densely and finely hairy, green, be- 

 coming brown. The leaves are ob- 

 long to broadly oval, firm in text- 

 ure, short-stalked, smooth or nearly 

 so on both sides when mature, 

 blunt or roimded at both ends, or 

 sometimes narrowed at the base, 2 

 to 7.5 cm. long, bright green above, fk. 630. — Pear-leaved Buckthom. 



