XXIV. RHAMNACEiE. 99 



genera all agree with that one, and differ from the adjoining 

 families in the position of the stamens, alternating with the 

 sepals, the petals either small and opposite to (or underneath) 

 the stamens, or wanting. 



The Ceanothuses of our gardens belong to this family. The Grape Vine, 

 the Virginian creeper, and other species of Vitis and Cissus, have the same 

 relative position of the stamens and sepals ; but the stamens being more 

 decidedly hypogynous, and the habit different, they form the indepen- 

 dent family Vitacece (or Ampelidece). 



1. RHAMNUS. BUCKTHORN. 



Shrubs, with alternate undivided leaves, and small green flowers on 

 short pedicels, usually clustered in the axils of the leaves. Calyx with 

 4 or 5 short deciduous teeth or sepals. Petals none or very small. 

 Stamens 4 or 5, alternating with the teeth of the calyx and opposite the 

 petals, inserted on a disk which lines the base of the calyx. Ovary free, 

 3- or 4-celled, with 1 erect ovule in each cell. Style very short. Fruit 

 a small berry (or drupe) enclosing 3 or 4 small 1 -seeded nuts. Embryo in 

 a fleshy albumen. 



A considerable genus, widely spread over the northern hemisphere, 

 both in the New and the Old World, penetrating into the tropics, with a 

 few southern species. 



The evergreen Alaternus of our shrubberies is a species of JRhamnus 

 (R. Alaternus) from southern Europe. 



Leaves minutely toothed. Branches often thorny. Flowers 



dioecious ; stamens 4 1. JR. catharticus. 



Leaves entire. No thorns. Flowers hermaphrodite; stamens 5 2. E. Frangula. 



1. H. catharticus, Linn. (fig. 225). Common B. — A glabrous shrub 

 with spreading branches, the smaller ones often ending in a stout thorn. 

 Leaves stalked, ovate, acuminate or pointed, rarely obtuse, 1 J to 2 inches 

 long, bordered by very small regular teeth, marked with a few prominent 

 veins, obliquely diverging from the midrib, and mostly proceeding from 

 below the middle. Flowers dioecious, very small, usually thickly clus- 

 tered in the axils of the leaves. Petals 4, very narrow, and not longer than 

 the teeth of the calyx. Fruit black, about the size of a pea. 



In hedges and bushy places, over Europe, Eussian Asia, and naturalised 

 in North America, but not Arctic. Not abundant in England or Ireland, 

 and very rare, if native, in Scotland. Fl. spring or early summer. 



2. R. Frangula, Linn. (fig. 226). Alder B.— A more erect shrub than 

 R. catharticus, not thorny, the leaves broader and more obtuse, entire 

 or slightly sinuate, having sometimes a minute down on the under side, 

 and the lateral veins more numerous, diverging equally from the midrib 

 almost the whole of its length. Flowers 2 or 3 together in each axil, 

 all hemaphrodite ; the minute petals, the teeth of the calyx, and the 

 stamens, in fives. Fruit dark purple, the size of a pea. 



In hedges and bushy places, throughout Europe and Russian Asia, 

 except the extreme north. In Britain rather more frequent than R. 

 catharticus, but still rare in Scotland and Ireland. Fl. spring or early 

 iummer. 



