Ill 



XCVI. RHAMNEvE. The Buckthorn Tribe. 



Rhamni, Juss. Gen. 376. (1789) ; RhamnEjE, Dec Prodr. 2. 19. (1825) ; Brongniart Memoire 

 &ur les Rliamnecs, (1826); Lindl. Synops. 72. (1829.) 



Diagnosis. Poljpetalous dicotyledons, with perigynous definite stamens 

 opposite the cucullate petals, concrete carpella, a superior ovarium with seve- 

 ral cells surrounded by a fleshy disk, solitary erect ovula, valvate calyx, and 

 alternate simple leaves with minute stipules. 



Anomalies. Sometimes the ovarium is inferior. Leaves opposite in Col- 

 letia and Rctanilla. Stipules and petals often wanting. 



Essential Character. — Calyx monophyllous, 4-5-cleft, with a valvate aestivation. Petals 

 distinct, cucullate, or convolute, inserted into the orifice of the calyx, occasionally wanting - . 

 Stamens definite, opposite the petals. Disk fleshy. Ovarium superior, or half superior, 2- 3- 

 or 4-celled; ovules solitary, erect. Fruit fleshy and indehiscent, or dry and separating - in 3 

 divisions. Seeds erect; albumen fleshy, seldom wanting - ; embryo almost as long - as the seed, 

 with large flat cotyledons, and a short inferior radicle. — Trees or shrubs, often spiny. Leaves 

 simple, alternate, very seldom opposite, with minute stipulcc. Flowers axillary or terminal. 



Affinities. Under this name have been for a long time confounded four 

 orders, very different in characters, and even in natural affinities, the peculiari- 

 ties of three of which have been pointed out by M. Ad. Brongniart in his me- 

 moir upon the subject, and a fourth has been distinguished by myself. These 

 orders are Rhamnea? properly so called, Celastrinea?, Ilicineae, and Staphylea- 

 cese, the respective affinities of which will be found under each. M. Brong- 

 niart indicates the relation that Rhamnea; bear, thus : if we take the insertion 

 of stamens as the most important distinction of plants, it will be found that 

 among polypetalous orders with perigynous stamens, Pomaceoe are those to 

 which Rhamneae have the closest relation, agreeing with them in the ovarium, 

 the cells of which are determinate in number, in the ascending ovules, and in 

 their alternate leaves usually having two stipule at their base ; the number and 

 position of their stamens, and the structure of their seeds, separate them wide- 

 ly. But if the insertion of the stamens is left out of consideration, they will 

 be found to have many characters in common with Biittneriaceas (Brown in 

 Flinders, 22.) ; such as, the aestivation of the calyx, the form of the petals, 

 the position of the stamens in front of those petals, the structure of the ova- 

 rium and seeds in many important points ; the principal differences between 

 them are, in fact, the stamens being turned outwards in Biittneriacere, which 

 are also destitute of a disk, have hypogynous stamens, and always two or 

 more ovules. Euphorbiaceas are allied to Rhamhese ; but the constant separa- 

 tion of stamens and pistils in the former family, hypogynous stamens and 

 suspended ovules, are all important marks of distinction. Nitrariaceas may 

 be compared with Rhamneaj in several points. 



Geography. Found over nearly all the world, except in the arctic zone ; 

 the maximum of species is said to be dispersed through the hottest parts of the 

 United States, the south of Europe, the north of Africa, Persia and India in 

 the northern hemisphere, the Cape of Good Hope and New Holland in the 

 southern. Some of the genera appear to be confined to particular countries, as 

 all the true Ceanothuses to North America, Phylicas to the Cape, Cryptandra 

 and Pomaderris to New Holland. 



Properties. The berries of various species of Rhamnus are violent pur- 

 gatives, and have been highly spoken of in dropsy. They also yield a dye, 

 varying in tint from yellow to green ; the ripe berries of R. catharticus, mixed 

 with gum arabic and lime-water form the green colour known under the name 

 of Bladder-green. The French berries of the shops (Graines d' Avignon, Fr.) 



