THE BUCKTHORNS 31 



and are enclosed by seven or eight pairs of over- 

 lapping scales, which are stipules in origin. The 

 leaves have their margins rolled inwards in the bud 

 and are in crowded tufts on the dwarf shoots and in 

 sub-opposite pairs on the long shoots ; they are 

 elliptical, with sharply-toothed margins and a short, 

 abrupt point, downy on the stalk and under-surface 

 when young, and of a dark green, which becomes 

 yellowish towards autumn. Their midribs give off 

 two or three secondary veins on either side at an 

 acute angle which sweep towards the apex in an 

 elliptical curve. On the other hand, the slightly 

 angular, violet-tinged twigs of the Alder Buckthorn 

 bear small grey hairy buds without scales ; and its 

 leaves, when unfolded, are reversedly egg-shaped, with 

 no teeth on their margins and with eight or nine 

 secondary veins on either side of their midribs. The 

 two species agree in having small half-moon-shaped 

 leaf-scars, each marked by the terminations of three 

 veins ; and, as we have seen, the lenticels are suf- 

 ficiently prominent to have attracted the notice of 

 Parkinson, who speaks of them as " white spots." 



The flowers of both species are alike individually 

 minute, but those of R. catharticus are yellowish- 

 green, and generally in dense clusters on the dwarf 

 shoots of the previous year ; they are dioecious, having, 

 that is, staminate and pistillate blossoms on distinct 

 bushes ; and their parts are in fours four sepals, four 

 petals, four stamens, a style generally four-branched, 

 and a four-seeded ovary. The few greenish-white 

 blossoms in the axils of the leaves of the Alder Buck- 

 thorn, though similar in the cup-shaped base of the 



