RHAMNACEAE (BUCKTHORN FAMILY) 561 



with only one erect seed in each cell, not ariUed. Petals folded inwards in the 

 bud, hooded or concave, inserted 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, ^\^th broad cotyledons, in sparse fleshy albumen. Flowers often 

 polygamous, sometimes 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. 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 2— t sepa- 



rate seed-like nutlets. 



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



3. Ceanothus. Petals long-clawed, hooded. Fruit dry, at length dehiscent. 



1. BERCHEMIA Neck. Supple-jack 



Calyx with a very short and roundish tube ; its lobes equaling the 6 oblong 

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

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

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

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

 panicles. (Name unexplained, probably personal.) 



L B. scandens (Hill) Trel. Glabrous ; leaves oblong-ovate, acute, scarcely 

 serrulate ; style short. {B. voluhilis DC.) — Damp soils, Va. to Mo., and south w, 

 June. — Stems tough and very lithe, whence the popular name. 



2. RHAMNUS [Tourn.] L. 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 pinnate-veined leaves, and greenish perfect, polygamous, or dioecious 

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



§ 1. EURHAmNUS Griseb. Flowers usually dioecious; nutlets and seeds 

 deeply grooved on the hack; rhaphe dorsal; cotyledons foliaceous, the mar- 

 gins revolute. 



* Calyx-lobes and stamens 5 ; petals wanting. 



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

 straight-veined; fruit 3-seeded. — Swamps, Nfd. to B. C, s. to N. J., Pa., 111., 

 Neb.^ Wyo., etc, June, 



* * Calyx-lobes, petals, and stamens 4. 



2. R. cavhArtvca L. (Common B.) Leaves ovate, minutely serrate ; fruit 

 3-4-seeded; branchlets rigid, often spine-like. — Cultivated for hedges; locally 

 naturalized eastw. May, June, (Tntrod. from Eu.) 



3. R. lanceolata Pursh, Tall unarmed shrub ; leaves oblong-lanceolate and 

 acute, or on flowering shoots oblong and obtuse, finely serrulate, smooth or 

 minutely downy beneath ; the yellowish-green flowers of two forms on distinct 

 plants, both perfect ; one with short pedicels clustered and with a short included 

 style ; the other with pedicels oftener solitary, style exserted ; petals deeply 

 notched; fruit 2-seeded. — Hills and river-banks, Pa. to Neb., southw- and 

 westw. May. 



GRATIS MANUAL — HG 



