268 Karl M. Wiegand and Arthur J. Eames 



Especially abundant on South Hill, and along the lake slopes from Cayuga 

 Heights northw. ; mostly absent on the chestnut soils and on the McLean gravels (?). 



Newf. to Minn., southw. to Fla., Okla., and La., including the Coastal Plain. 



The leaves are not so dull as several textbooks represent them to be, but are very 

 lustrous, at least when mature. 



Plants apparently of hybrid origin between this species and R. Eglanteria are 

 common. They show various combinations of leaf form, glandularity, and shape 

 of prickles. 



22. Prunus (Tourn.) L. 



a. Flowers subsessile, large, pink ; drupe downy ; stone sculptured ; leaves con- 

 duplicate. 1. P. Persica 

 a. Flowers pedicelled, large or small, white ; drupe glabrous ; stone not sculptured ; 

 leaves conduplicate or convolute. 

 b. Flowers umbellate, rarely subcorymbose or solitary, not from leaf-bearing buds 

 (except in no. 7). 

 c. Leaves convolute ; fruit large except in no. Sa, 2-4 cm. long, sulcate ; stone flat- 

 tened; twigs in winter usually not terminated by a bud. (Plums.) 

 d. Leaves acuminate, glabrous or nearly so when mature ; fruit reddish 

 yellow. 

 e. Sepals very broad and obtuse, subglabrous, not serrate nor red; leaves 

 small, the blade 3-5 cm. long, crenate-serrate, the petiole 5-14 mm. 

 long; petiolar glands nearly or quite wanting. 2. P. cerasifera 

 e. Sepals ovate-lanceolate ; calyx and stamens often purplish ; leaves large, 

 the blade 5-8 cm. long, the petiole 7-15 mm. long; petiolar glands 

 strongly developed. 

 /. Sepals entire, tomentose within ; leaves sharply serrate. 



3. P. americaha 

 f. Sepals glandular-serrate, glabrous ; leaves with crenate gland-tipped 

 teeth. 4. P. nigra 



d. Leaves obtuse or acutish, downy beneath ; calyx and stamens not purplish ; 

 fruit blue-black. 

 e. Blade 5 cm. long or more ; flowers 2-2.5 cm. in diam. ; fruit 3-4 cm. long. 



5. P. domestica 

 e. Blade 2.5-4 cm. long; flowers 0.8-1.5 cm. in diam.; fruit 1.2-2 cm. long. 



5a. P. d., var. insititia 

 c. Leaves conduplicate; fruit smaller (2 cm. long or less), not sulcate; stone 

 subglobose ; twigs in winter with a terminal bud. (Cherries.) 

 d. Plant dwarf, 1.5 m. high or less ; leaves spatulate-oblong, pale beneath, 



with low sharp distant teeth. 6. P. susquehanae 



d. Plant arborescent; leaves lanceolate or obovate, simply or doubly crenate. 

 e. Flowers 2-3 cm. in diam., umbellate; fruit 15-20 mm. in diam; leaves 

 oblong-obovate, abruptly short-acuminate, coarsely doubly crenate- 

 dentate ; bark of branches dull dark ashy-brown. 

 /. Leaves firm, waxy, glabrous or nearly so from the first ; veins 6-8 

 pairs; flower spurs leafy; flower-bud scales scarcely enlarging, erect, 

 3-8 mm. long or less ; sepals crenate ; fruit sour. 



7. P. cerasus 

 f. Leaves thin, veiny, hairy when -young; veins 10-14 pairs; flower spurs 

 leafless; flower-bud scales enlarging, recurved, 10-15 mm. long; sepals 

 entire; fruit sweet. 8. P. avium 



e. Flowers 1.5 cm. in diam. or less, often subcorymbose ; fruit 7-8 mm. 

 in diam. ; leaves oblong-lanceolate, gradually pointed, very finely and un- 

 equally crenate-dentate ; bark of branches reddish bronze. 



9. P. pennsylvanica 



