ROSACEA. (rose family.) 151 



IT. Ovaries inferior or enclosed in the calyx-tube. 



Tribe V. POTERIE^E. Pistils 1-4, becoming achenes, completely enclosed in the 

 dry and firm calyx-tube, which is constricted or nearly closed at the throat. Herbs 

 with compound or lobed leaves. Petals often none. 



12. Alcheniilla* Calyx urceolate, bracteolate. Petals none. Stamens 1-4. Flowers 



minute, clustered. 



13. Agrinionia. Calyx turbinate, with a margin of hooked prickles. Stamens 5-12. 



Flowers yellow, in long racemes. 



14. Poterium. Calyx-lobes petaloid ; tube 4-angled, naked Petals none. Flowers den.sely 



capitate or spicate. 

 Tribe VI. KOSE^. Pistils many, becoming bony achenes, enclosed in the globose or 

 urn-shaped fleshy calyx-tube, which resembles a pome. Petals conspicuous. Stamens 

 numerous. 



15. Kosa. The only genus. Prickly shrubs with pinnate leaves. 



Tribe VII. POME..E. Carpels 2-5, enclosed in and coalescent with the fleshy or berry- 

 like calyx, in fruit becoming a 2 -several-celled pome. Trees or shrubs, with stipules 

 free from the petiole. 



a. Cells of the compound ovary as many as the styles (2-5), each 2- (rarely several-) ovuled. 



16. Pjnrus. Pome containing 2-5 papery or cartilaginous carpels. 



17. Crataegus. Pome drupe-like, with 1-5 bony stones or kernels. Usually thorny. 

 b. Cells of the compound ovary becoming twice as many as the styles, each 1-ovuled. 



18. Amelanchier. Pome usually of 5 carpels : each becomes incompletely 2-ceUed by a 



projection from its back ; otherwise as Pyrus. 



1. PRtJNUS, Tourn. Plum, Cherry, etc. 



Calyx 5-cleft ; the tube bell-shaped, urn-shaped or tubular-obconical, decidu- 

 ous after flowering. Petals 5, spreading. Stamens 15-20. Pistil solitary, 

 with 2 pendulous ovules. Drupe fleshy, with a bon\^ stone. — Small trees or 

 shrubs, with mostly edible fruit. (The ancient Latin name.) 



§ 1. PRUNUS proper (and Cerasus). Drupe smooth, and the stone smooth or 

 someivhat rugged ; flowers (usuaJli/ white) from separate lateral scaly buds 

 in early spring , preceding or coetaneous with the leaves; the pedicels Jew or 

 several in simple umbel4ike clusters. 



1. P. Americana, Marshall. (Wild Yellow or Red Plum.) Tree 

 thorny, 8-20° high; leaves ovate or somewhat obovate, conspicuously pointed, 

 coarsely or doubly serrate, very veiny, glabrous when mature ; fruit nearlv desti- 

 tute of bloom, roundish-oval, yellow, orange, or red, i - f in diameter, with 

 the turgid stone more or less acute on both margins, or in cultivated states I' 

 ,or more in diameter, the flattened stone with broader margins ; pleasant-tasted, 

 but with a tough and acerb skin. — Woodlands and river-banks, common. 



2. P. maritima, AVang. (Beach Plum.) Low and straggling (1 - 5°) . 

 leaves ovate or oval,fl7iely serrate, softly pubescent underneath ; pedicels short, 

 pubescent ; fruit globular, purple or crimson with a bloom (4- 1' in diameter) ; 

 the stone very turgid, acute on one edge, rounded and minutely grooved on the 

 other. — Sea-beaches and the vicinity, N. Brunswick to Ya. It varies, when at 

 some distance from the coast (N. J. and southward), with the leaves smoother 

 and thinner and the fruit smaller. 



3. P. Alleghaniensis, Porter. A low straggling shrub or small tree 

 (3-15° high), seldom thorny; leaves lanceolate to oblong-ovate, often long-acu- 



