CLASSIFICATION OF ANGIOSPERMS. 287 



f. ROSACEA OR ROSE FAMILY.— The plants are herbs, 

 shrubs or trees usually with alternate, stipulate, simple or com- 

 pound leaves, and regular perfect flowers with or without petals, 

 and numerous stamens (Fig. 134, D). The fruit is a pome, drupe, 

 follicle or akene (Fig. 89). 



Primus serotina or wild black cherry is a tree varying from 

 10 to 30 M. in height, with a more or less smooth bark marked by 

 prominent transverse lenticels, and showing a tendency to peel 

 off in semicircular pieces, which gives the older bark, which is 

 more or less black, a roughened appearance. The leaves and inner 

 bark have an agreeable aromatic odor; the leaves are oval- or 

 oblong-lanceolate, acute or acuminate, serrate, the teeth being 

 glandular ; the flowers are white and in racemes ; the fruit is a 

 dark purple or blackish, globular drupe (Fig. 235). The nearly 

 related species wild cherry or choke cherry (P run us virginiana) 

 is a shrub or small tree with broadly oval, acuminate leaves, red 

 or nearly black drupes, and flowers and fruits several weeks 

 earlier than P. serotina (p. 538). 



Prnnus Amygdalus is a small tree resembling somewhat the 

 peach tree. The leaves are lanceolate', serrate ; the flowers are 

 rose-colored, and the fruit is a dehiscent drupe in which the 

 leathery sarcocarp separates from the endocarp, which latter, with 

 the seed which it encloses, constitutes the almond of the market 

 (Fig. 187). The kernels of some of the seeds are bitter (bitter 

 almonds, p. 433), and some are bland and free from bitterness. 

 By a process of selection plants yielding the latter are now ex- 

 tensively cultivated in sub-tropical and warm-temperate regions, 

 and yield the sweet almond (p. 434) of the market. In Turke- 

 stan some of the almonds have a smooth endocarp. 



A glucosidal substance having the properties of amygdalin is 

 found in the buds, leaves, bark and seeds, more especially the 

 latter, of some members of the following genera : Prunus, Sorbus 

 (mountain ash), Cotoneaster, Amelanchier, and Eriobotyra (£. 

 japonica or Japanese medlar). 



Prunus domestica yields the French plum or prune of 

 commerce (p. 576). The leaves are ovate or ovate-lanceolate, 

 dentate, and pubescent on the lower surface. The flowers are 

 greenish-white, with a hairy peduncle. The fruit is a drupe with 



