112 RHAMNACE^E. PACHYSTIMA. 



RHAMNUS. 



2 PACHYSTIMA Raf. Am. Month. Mag. 1818. 



Low evergreen shrubs with opposite leaves, and small flowers 

 in 1 -few-flowered axillary cymes. Calyx with a short obconical 

 tube and four rounded lobes. Petals 4. Stamens 4, inserted at 

 the edge of the broad disk which lines the calyx-tube. Ovary 

 free, 2-celled : style .very short : capsule 2- valued, 1-2-seeded. 

 Seeds enclosed in a white, many-cleft membranous aril. 



P. Myrsinites Raf. 1. c. Densely branched to nearly simple, 1-3 feet 

 high: leaves smooth, ovate to oblong or lanceolate, cuneate at base, the 

 upper half serrate or serrulate, %-\ in-h long on very short peduncles : 

 flowers a line or two long: fruit 2 lines long, smooth. In the mountains, 

 from Brit. Columbia to California and the Rocky Mountains. 



ORDER XXII. KHAMNACEJE Dumort. Fl. Belg. 102. 



Trees or shrubs, the branches often thorny. Leaves simple 

 with minute stipules. Flowers small, sometimes by abortion dioe- 

 cious, monoecious or polygamous. Calyx 4-5-cleft, valvate in the 

 bud. Petals distinct, cucullate, (each wrapped around a stamen) 

 narrowed at base, inserted upon the throat of the calyx, some- 

 times wanting. Stamens as many as the lobes of the calyx and 

 alternate with them. Ovary 24, united carpels, 2-4-celled, free 

 from or usually cohering with the tube of the calyx or more or 

 less immersed in the fleshy perigynous disk : ovules solitary, erect. 

 Styles more or less connate : stigmas simple usually distinct. 

 Fruit free or commonly more or less cohering with the calyx, 

 fleshy and indehiscent or with the carpels dry and at length sep- 

 arable. Seeds erect, anatropous, with a large, straight embryo 

 in sparing fleshy albumen. 



1. Rhamnus. Calyx and disk free from the ovary: calyx-lobes erector 

 spreading : fruit berry-like. 



2. Ceanothus. Calyx and disk adnate to the base of the ovary : calyx- 

 lobes connivent. Fruit dry or nearly so. 



1 RHAMNUS L. Gen. n. 265 in part. 



Shrubs or small trees with alternate petioled pinnately veined 

 leaves, small deciduous stipules and axillary cymose or racemose 

 flowers. Flowers perfect or polygamo-dioecious. Calyx 4-5-cleft, 

 with erect or spreading lobes, the campanulate tube lined with 

 the disk and persistent. Petals 4 or 6 or more, inserted on the 

 margin ot the disk : claws short. Stamens 4 or 5 : filaments very 

 short. Ovary free, 2-4-celled : style short, 3-4-cleft. Fruit bac- 

 cate, containing 2-4 cartilaginous 1-seeded nutlets, mostly inde- 

 hiscent. 



1 RHAMNUS Brongn. Ann. Sc. Nat. x, 360. Seeds and nut- 

 lets deeply sulcate or concave on the back, the raphe in the 

 hollow: flowers mostly diuH-ioiis, solitary or foscicled in the 

 axils. 



R. ii ! n i folia L'Her. Sort. Angl. o. Shrub 2-4 feet high : leaves decid- 

 uous, ovate- oblong, acute at each end or acuminate, 2 or 3 inches long, 

 crenately serrate, the slender petioles slightly puberulent : lobes of the 



