Black Sloe 



487 



Calyx-lobes without glands, not ciliate. 

 Leaves acute to acuminate; eastern tree. 

 Leaves obtuse; Oregon and California tree. 

 Calyx -lobes glandular-ciliate or ciliate. 

 Calyx-lobes serrate and glandular. 

 Calyx -lobes pubescent on both sides. 

 Calyx-lobes pubescent on inner side only. 

 Umbels only i- to 3- flowered; introduced European trees. 

 Flowers usually solitary; twigs spiny; leaves oblong to ovate. 

 Flowers usually in pairs; twigs mostly not spiny; leaves ovate to 

 obovate. 

 Cherries; fruit without ventral groove; stone globose or subglobose. 

 Flowers in lateral umbels, corymbs or fascicles, appearing with or 

 before the leaves. 

 Flowers umbellate or fascicled, not corymbose; introduced Euro- 

 pean trees. 

 Leaves glabrous; pedicels short; fruit sour. 



Leaves pubescent at least on the veins; pedicels long; fruit sweet. 

 Flowers corymbose, but the axis of the corymb often short; native 

 trees. 

 Leaves acute to acuminate; eastern tree. 

 Leaves obtuse or rarely acute; western trees. 

 Leaves glabrous. 

 Leaves pubescent. 

 Flowers in terminal corymbs at the ends of twigs of the season; intro- 

 duced European tree. 



6. P. americana. 



7. P. subcordata. 



8. P. angustijolia. 



9. P. horlidana. 



10. P. nigra. 



11. P. spinosa. 



12. P. domestica. 



13. P. Cerasus. 



14. P. Avium. 



15. P. pennsylvanica. 



16. P. emarginata. 



17. P. prunijolia. 



18. P. Mahaleh. 



I. BLACK SLOE Prunus umbellata Elliott 



Also called Southern sloe, Hog, Prai- 

 rie, Oldfield, Chicasaw, or Bullace plum, 

 this is a small tree, frequent in river 

 swamps and in hammocks of the coastal 

 region, from South Carolina to Louisiana, 

 north to Arkansas. Its maximum height 

 is 6 meters, with a trunk diameter of 3 

 dm. 



The trunk is slender, usually erect, 

 but often ascending, with wide-spread- 

 ing branches; the bark is about 8 mm. 

 thick, separating into persistent, dark 

 brown scales; the twigs are more or less 

 densely hairy, soon becoming smooth and 

 shining, light red, changing to dark 

 brown. The winter buds are very small. 

 The leaves are rather thin, oblong, el- 

 liptic or nearly oval, 5 to 7 cm. long, 



Fig. 444. Black Sloe. 



