Buckthorns (Rhamnus)

..... OT AT AE .....
    twigs hairless, red gray twigs twigs somewhat hairy
sepals 4-5; fruit black ..... alder-lvd b.t. (3.alnifolia) swamps & bogs; NF to NJ 7 PA ..... .....
seps & stamens each 5; no petals common b.t. (6.cathartica = purging) fruit black; Eurasian escape ..... ..... .....
sepals & petals and stamens each 4 (5.citrefolia) Asian, sparingly introduced lance-leaf b.t. (4.lanceolata) X; moist, esp calcareous soil; s PA s ..... .....
sepals & petals 5; fruit red, turning black ..... ..... Carolina b.t. (2.caroliana) X; minutely serrulate lvs; moist woods & alluvial soil, esp on coastal plain; se VA to FL European b.t. (1.frangula = the L. name) Eurasian escape; esp. in wet soil; NS to NJ, KY