THE PLUMS OF NEW YORK. 



D.D. Leaves round-ovate, obtusely, sometimes doubly 

 serrate; petioles glandless; calyx-lobes pubescent on 

 both surfaces; fruit dark red or purplish; stone turgid, 



pointed at both ends 14. P. subcordata. 



C.C. Leaves narrow, lanceolate-ovate. 

 D. Leaves flat. 



E. Leaves glabrous; fruits globular, usually pur- 

 ple at maturity but sometimes red or orange- 

 red; bloom thin; stone turgid, cherry-like 15. P. umbellate. 



E.E. Leaves pubescent. 



F. Stone acute at both ends; fruit purple. 16. P. mitis. 

 F.F. Stone rounded at base; fruits vari- 

 ously colored 17. P. tarda. 



D.D. Leaves more or less folded upward. 



E. Fruits small, J inch in diameter, cherry-like; 

 leaves lanceolate, upper surface glabrous, 

 lustrous, lower surface pubescent in axils of 

 veins, marginal teeth glandless; petioles bi- 

 glandular; stone small, ovoid, turgid, cherry- 

 like; rarely a tree; tender in New York 18. P. angustifolia. 



E.E. Fruits large, an inch in diameter, plum- 

 like; leaves lanceolate, peach-like, upper sur- 

 face glabrous, lower surface pubescent along 

 the midrib; petioles with from i to 6 glands; 

 stone compressed and pointed at both ends; 



usually a tree; hardy in New York 19. P. munsoniana 



B.B. Plants shrubs. 



C. Fruits dark purple. 



D. Leaves ovate, acute, finely serrated ; shoots becoming 



glabrous; stones pointed at both ends 20. P. maritima. 



D.D. Leaves oval-orbicular, crenate-serrate; shoots 



usually pubescent; stone pointed only at the base. .21. P. gravesii. 

 C.C. Fruits red or orange, sometimes yellow but never deep 

 purple. 



D. Fruits large, i inch in diameter; leaves oblong- 

 ovate, long-pointed, margin serrate with incurved 

 sometimes glandular teeth, upper surface glabrous, 

 lower surface pilose; petiole with i or 2 glands; stone 



oval, flattened 22 - p - orthosepela. 



D.D. Fruits small, i inch in diameter. 



E. Leaves small, ovate-lanceolate or oval, mar- 

 gins finely and evenly serrate, upper surface 

 glabrous, lower surface soft pubescent; petioles 

 short and stout; fruits variable in color, mostly 



red; stone turgid, pointed at both ends 23- P- gracilis. 



E.E. Leaves oblong-ovate, margins coarsely or 

 doubly serrate, glabrous above and sparingly 

 pubescent below; petiole glandular; fruits 

 cherry-red 2 4- P. rivularis. 



