676 



The Buckthorns 



Rhamnus Frangula), one occurs in the West Indies, and several in Mexico and 

 Central America. It was to R. cathartica Linnaeus, the type species, to which the 

 Greek name, now the name of the genus, was originally applied. 



The Buckthorns have bitter bark, alternate simple usually toothed leaves, 

 with small stipules, which fall away early, and small green clustered axillary 

 flowers, either perfect or imperfect. The calyx is 4-lobed or 5-lobed, with a bell- 

 shaped tube; there arc 4 or 5 petals, each wrapped around a stamen, or in some 

 species none; the 4 or 5 short stamens are alternate with the calyx-lobes, borne on 

 the edge of the disk; the ovary is from 2-celled to 4-celled, each cavity containing 

 I ovule; the style is short or slender, the stigmas as many as the cavities of the 

 ovary; the fruit is a small drupe, containing 2 to 4 nutlets. 



The arborescent forms of the United States may be distinguished as follows: 



Leaves deciduous; flowers perfect; nutlets rounded on the back. 



Peduncles shorter than the petioles; eastern tree. 



Peduncles longer than the petioles; western tree. 

 Leaves persistent; flowers polygamous or dioecious; nutlets grooved on the 

 back; Califomian trees. 



Leaves spinulose-serrate. 



Leaves not spinulose, glandular-serrate. 



1. R. caroliniana. 



2. R. Purshiana. 



3. R. ilicifolia. 



4. R. pyrijolia. 



I. INDIAN CHERRY Rhamnus caroliniana Walter 



This species grows along streams and on hillsides from Virginia to Florida, 

 southern Ohio, IlHnois, Kansas, and Texas, often a mere shrub, but sometimes 



forming a tree 12 meters high, with a trunk 

 2 dm. thick ; it is also called Yellowwood and 

 Polecat-tree. 



The bark is thin, smooth, or slightly fur- 

 rowed, light gray. The young twigs are 

 reddish brown and finely hairy, becoming 

 smooth and gray. The leaves are oblong 

 to elHptic, quite densely velvety-hairy when 

 young, pointed, entire-margined, rounded or 

 narrowed at the base, rather firm in texture, 

 when mature 5 to 12 cm. long, dark green 

 and somewhat shining on the upper sur- 

 face, paler and smooth or slightly hairy on 

 the under side; their stalks are 8 to 18 mm. 

 long. The flowers are in small stalked hairy 

 clusters in the leaf-axils, opening from April 

 to June ; the calyx-lobes are triangular-ovate, 

 pointed, nearly or quite as long as the calyx- 

 tube; the 5 ovate notched petals are much shorter than the calyx-lobes; there are 

 5 very short stamens opposite the petals and partly enfolded by them; the ovary 



Fig. 627. Indian Cherry. 



