DIV. n 



AtfGIOSPERMAE 



663 



Potentilla with a number of British species has a flattened receptacle, epicalyx, 

 and an apocarpous pistil. Geum and Dryas have hairy carpels which elongate in 

 fruit and are distributed by the wind. Fragraria, Strawberry, with small achenes 

 situated on the succulent, enlarged, floral receptacle. Rubus, Blackberry, has 

 numerous species, mostly scrambling shrubs with recurved prickles. Leaves 



FIG. 



)7. Primus remfus ( rial. size). 1, Flowering shoot ; 2, flower cut in two 

 (slightly enlarged) ; 3, fruits ; It, fruit cut through longitudinally. 



trifoliate. E. iclaeus, the Raspberry, is one of the few species which are not 

 straggling climbers. The small drupes are closely crowded on the convex receptacle, 

 forming the collective fruit. 



The group of the Pruneae which includes a number of important trees bearing 

 stone-fruits has a single carpel situated in the middle of the flat expanded floral 

 receptacle (Fig. 692 B}. Prunus cerasus, the Wild Cherry (Fig. 697) ; P. avium, 

 Gean ; P. domestica, the Plum; P. arrncniaca, the Apricot, and P. persica, the 

 Peach, are of Chinese origin ; P. Amygdalus, the Almond, from the eastern Mediter- 

 ranean region. The succulent mesocarp of the Almond dries up as the fruit ripens 

 and ruptures, setting the stony endocarp free. 



