RHAMNACE^. (BUCKTHORN FAMILY.) Ill 



Order 27. RHAMNACE^. (Rccktiiorn Family.) 



Shrubs or small trees, with simple leaves, small and regular flowers {some- 

 times apetalous), with the 4 or 5 perigijnous stamens as many as the valvate 

 sepals and alternate with them, accordingly opposite the petals! Drupe or 

 pod with only one erect seed in each cell, not arilled. — Petals folded in- 

 wards in the bud, hooded or concave, inserted along with the stamens 

 into the edge of the fleshy disk which lines the short tube of the calyx 

 and sometimes unites it to the lower part of the 2-5-celled ovary. 

 Ovules solitary, anatropous. Stigmas 2 - 5. Embryo large, with broad 

 cotyledons, in sparing fleshy albumen. — Flowers often polygamous, some- 

 times dioecious. Leaves mostly alternate ; stipules small or obsolete. 

 Branches often thorny. (Slightly bitter and astringent; the fruit often 

 mucilaginous, commonly rather nauseous or drastic.) 

 * Calyx and disk free from the ovary. 



1. Bercheiuia. Petals sessile, entire, as long as the calyx. Drupe with thin flesh and a 



2-celled bony iiutamen. 



2. Rliainnus. Petals small, short-clawed, notched, or none. Drupe berry-like, with 2-4 



separate seed-like nutlets. 



, * * Calyx with the disk adherent to the base of the ovary. 



3. Ceanotlius. Petals long-clawed, hooded. P'ruit dry, at length dehiscent. 



1. BERCHEMIA, Necker. Supple-Jack. 



Calyx with a very sliort and roundish tube ; its lobes equalling the 5 oblong 

 sessile acute petals, longer than the stamens. Disk very thick and flat, filling 

 the calyx-tube and covering the ovary. Drupe oblong, with thin flesh and a 

 bony 2-celled putamen. — Woody high-climbing twiners, with tiie pinnate veins 

 of the leaves straight and parallel, the small greenish-white flowers in small 

 panicles. (Name unexplained, probably personal.) 



1. B. volubilis, DC. Glabrous; leaves oblong-ovate, acute, scarcely 

 seiTulate ; style short. — Damp soils, Va. to Ky. and jNIo., and southward. 

 June. — Ascending tall trees. Stems tough and very lithe, whence the poj)- 

 ular name. 



2. RHAMNUS, Tourn. Buckthorn. 



Calyx 4 - 5-cleft ; the tube campanulate, lined with the disk. Petals small, 

 short-clawed, notched at the end, wrapped around the short stamens, or some- 

 times none. Ovary free, 2-4-celled. Drupe berry-like (black), containing 

 2-4 separate seed-like nutlets, of cartilaginous texture. — Shrubs or small 

 trees, with loosely pinnately veined leaves, and greenish polygamous or dioe- 

 cious flowers, in axillary clusters. (The ancient Greek name.) 



§ 1. KHAMNUS proper. FUnccrs usually dtaciuus ; nutlets and seeds deeply 

 grooved on the back ; rhaplie dorsal ,- cotyledons foliaceous, (he jitargins 

 revolute. 



* Calyx-lobes and stamens 5; petals wanting. 



1. R. alnifblia, L'Her. A low shrub; leaves oval, acute, serrate, nearly 

 straight-veined; fruit 3-seeded. — Swamps, Maine to Peuu., Neb., and north- 

 ward. June. 



