SECT. II 



PHANEROGAMIA 



615 



{d) PofcntiUeac. — Floral receptacle plate-shaped, flat or convex and bearing 

 numerous free carpels which develop into nutlets, drupes, or berries. Each carpid 

 with one ovule. Epicalyx often present. Polciitilla with a number of British 

 species (Fig. 625, 1). Geum and Dnjas have hairy carpels which elongate in fruit 

 and are distributed by the wind. The latter genus includes arctic and alpine 

 forms. Fragraria, Strawberry, with small achenes situated on the succulent, 

 enlarged, floral receptacle. Ruhiis, Blackberry, has numerous species, mostly 

 scrambling shrubs with recurved prickles. Leaves trifoliate. E. idaeus, the 

 Raspberry, is one of the few species which are not straggling climbers (Fig. 630). 

 The small drupes are closely crowded on the convex receptacle, only slightly con 

 nected with one another. The withered style is for a long time visible on the 

 partial fruits. R. fruticosus. 



(e) Pruneae.— Flower perigynous, with a single carpel seated on the cup-shaped 



Fig. 630. — Riihus id'irus. Flowering branch ami tVuits. (A nat. size.) 



receiitacle (Fig. 624 B). Ovules two. Fruit, a one-seeded drupe. The group 

 includes a number of important fruit trees. Prunus cerasiis, the Wild CheiTy 

 (Fio'. 631) ; P. avium, Gean ; P. domestica, the Plum ; P. armeniaca, the Apricot, 

 and P. pcrsica, the Peach, are of Chinese origin ; P. Amygdalus, the Almond, from 

 the eastern Mediterranean region. The two last-named species have hairy fruits. 

 The succulent mesocarp of the Almond dries up as the fruit ripens, and ruptures, 

 setting the stony endocarp free. 



(/') Chrysohalaaeac. — Frequently with dorsi ventral flowers. A single carpel. 



Poisonous. — The seeds of many Rosaceae contain amygdalin, but usually not 

 in such amount as to be poisonous, owing to the resulting hydrocyanic acid, when 

 eaten fresh in small quantity ; this is, however, often the case with the residuum 

 left after the seeds, e.g. of bitter almonds, have been crushed. The leaves of the 

 Cherry Laurel {Pruims laurocen sus) may also give rise to toxic eft'ects. 



Official. — Rosae gallicae pktala from cultivated plants of Rosa gallica ; 



