WINTER KEY TO THE SPECIES OF PRUNUS
| a. | Terminal bud present; bark of young trunks rather smooth. | |||
| b. | Buds clustered at the tips of all shoots; twigs usually lessthan 1/16 inch thick; pith of twigs brown. | P. pennsylvanica, p. [159]. | ||
| bb. | Buds not clustered, or clustered only on short, spur-likebranchlets; twigs usually more than 1/16 inch thick; pithof twigs white. | |||
| c. | Buds usually 1/4 inch or less in length; bud-scales uniformin color, apiculate at the apex; bark on old trunksblackish, rough-scaly; small to large tree. | P. serotina, p. [155]. | ||
| cc. | Buds usually 1/4-1/2 inch long; bud-scales grayish on themargins, rounded at the apex; bark on old trunks brown,smooth or only slightly fissured; usually a large shrub. | P. virginiana, p. [157]. | ||
| aa. | Terminal bud absent; bark of young trunks early splittingoff in large, thick plates. | P. nigra, p. [161]. | ||
Black Cherry
1. Winter twig, × 1.
2. Portion of twig, enlarged.