RHAMNACE^E. (BUCKTHORN FAMILY.) 79 



or pod with only one seed in each cell, not drilled Petals folded inwards 

 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 often 

 unites it to the lower part of the 2-5-celled ovary. Ovules solitary, 

 anatropous, erect. Stigmas 2-5. Embryo large, with broad cotyledons, 

 in sparing fleshy albumen. Flowers often polygamous. Leaves mostly 

 alternate: stipules small or obsolete. Branches often thorny. (Slightly 

 bitter and astringent : the fruit often mucilaginous, commonly rather nau- 

 seous or drastic.) 



Synopsis. 



* Calyx and disk free from the ovary. 



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



2-celled bony putamen. 



2. RHAMNUS. Petals small, short-clawed, notched, or none. Drupe berry-like, with the 



2-4 separate seed-like nutlets concave on the back : cotyledons leaf-like, revolute. 

 8. ERANGULA. Petals, &c. as in No. 2. Seed-like nutlets convex on the back : cotyledons 

 plane, fleshy. 



* * Calyx with the disk coherent with the base of the ovary. 

 4. CEANOTHUS. Petals long-clawed, hooded. Fruit dry, at length dehiscent. 



1. BE SIC II EMI A, Necker. SUPPLE-JACK. 



Calyx with a very short 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 twining and climbing vines, with the pinnate 

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

 small panicles. (Name unexplained.) 



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

 serrulate ; style short, 2-toothed at the apex. Damp soils, Virginia, and 

 southward. June. Ascending tall trees. Stems tough and very lithe, whence 

 the popular name. 



2. RHAMNUS, Tourn. BUCKTHORN. 



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

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

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

 arate seed-like nutlets, of cartilaginous texture, which arc grooved on the back, 

 as is the contained seed. Cotyledons foliaceous, the margins revolute. Shrubs 

 or small trees, with loosely pinnately veined leaves, and greenish polygamous or 

 dioecious flowers in axillary clusters. (The ancient Greek name, from the nu- 

 merous branchlets.) 



* Lobes of the calyx, petals, and stamens 4. 



1. K. CATHARTICUS, L. (COMMON BUCKTHORN.) Leaves ovate, minutely 

 serrate; fruit 3 - 1-seeded ; branchlets thorny. Cultivated fcr hedges; spon- 

 taneous on the Hudson River, New York. (Adv. from Eu.) 



