KHAMNACE^. (BUCKTHORN FAMILY.) 79 



or pod icith only one seed in each cell, not untied. — 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-ceIled 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. 



3. FRANGULA. 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. BERCHEMIA, Neckcr. 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. Drape 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, Toum. 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 sometimes 

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

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

 as is the contained seed. Cotyledons foliaccous, the margins revolute. — Shrubs 

 or small trees, with loosely pinnately veined leaves, and greenish polygamous 01 

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

 merous branchlets.) 



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



1. R. CATnARTicus, L. (Common Buckthorn.) Leaves ovate, minutely 

 serrate; fruit 3 - 4-seeded '; branchlets thorny. — Cultivated for hedges; spon- 

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



