64 RHAMNUS CATHARTICUS 



calyx-tube but free from it, 4-celled, with one erect ovule in each 

 cell ; style cleft about half-way down into 4 blunt branches. Fruit 

 fleshy, round, about the size of a pea, umbilicated at the apex, 

 surrounded at the base by a circular persistent portion of the calyx- 

 tube, shining, at first green, then black ; skin thin ; pulp scanty, 

 containing 4 hard, indehiscent, dark-brown stones (pyrenes), which 

 are obovoid, grooved on their outer surface, where the walls are 

 folded inwards, hollow in the centre, angled at the inner edge, 

 where they meet in the middle of the fruit. Seeds one in each 

 stone, furrowed deeply on back, shallowly on front, curved from 

 side to side in a revolute manner (so as to make a horseshoe on 

 section) round the central cavity of the stone, the convexity 

 inwards ; embryo in the axis of scanty endosperm, and similarly 

 curved, cotyledons large, raphe running to the top of the seed in 

 the dorsal furrow. 



Habitat. In England this shrub is chiefly, though not exclu- 

 sively, found in chalky districts, where it occurs in thickets and 

 small woods. It is not unfrequent in the south, but becomes rare 

 northwards, and is not native in Scotland. In Europe it is found 

 in all parts except the extreme north, and extends far eastwards 

 into Siberia ; it has also been observed in Algeria, and is culti- 

 vated in the United States. The structure of the fruit is remark- 

 able and quite unlike that of a true berry, to which its outward 

 appearance is so similar ; one or two of the stones are frequently 

 abortive. 



Syme, E. Bot., ii, p. 226; Hook, f., Stud. Fl., p. 82; "Wats., 



Comp. Cyb. Br., p. 136 ; Gren. and Godr., Fl. France, i, p. 335 ; 



Lindl. FL Med., p. 167. 



Official Part and Name. EHAMNI Succus. The recently ex- 

 pressed juice of the ripe berries (B. P.). The recently expressed 

 juice of the ripe berries (Ehamni Succus, Buckthorn juice (I. P.). 

 Not official in the Pharmacopoeia of the United States. 



Collection'. Buckthorn fruits are plentiful in certain parts 

 of Hertfordshire, Oxfordshire, Buckinghamshire, Wiltshire, 

 and some other counties in England, and from these parts 



