TREES AXD SHRUBS 121 



4. RHAMNUS L. Buckthorn 



Unarmed shrul s with rather large, alternate leaves, over 3 

 feet high; flowers perfect or polygamo-dioecious, in small axillary 

 clusters; sepal 4 or 5: disks lining the hypanthium: petals 4 or 5, 

 sometimes wanting, (-lawless, on the margin of the hypanthium; 

 stamens 4 or 5, inserted on the edge of the disk: ovary 2 to 4-eelled; 

 fruit a 2 to 4-seeded rather dry berry. 



Flowers fascicled. 2 or 3 in each axil; leaves 

 small, 1% inches long or less, yellowish be- 

 neath; seeds 2. 1. R. fasciculata. 



Flowers in peduncled cymes, numerous; leaves 

 usually more than 1% inches long, not yel- 

 lowish beneath. 



Seeds 2; leaves pale beneath with a dense 



tomentulous pubescence. 2. R. ursina. 



Seeds 3; leaves green on both surfaces, spar- 

 ingly pubescent beneath. 3. R. betulaefolia. 



