112 RHAMNACE. 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-valved, 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, 4-1 inch 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. 
OrpeR XXII. RHAMNACEA! Dumort. Fl. Belg. 102. 
Trees or shrubs, the branches often thorny. Leaves simple 
with minute stipules. Flowers small, sometimes by abortion dice- 
cious, moncecious or polygamous. Calyx 4—6-cleft, valvate in the 
bud. Petals distinet, 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 2-4, 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 distinet. 
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 erect or 
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-diacious. 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 bae- 
cate, containing 2-4 cartilaginous 1-seeded nutlets, mostly inde- 
hiscent. 
§ 1 Ruamnus Brongn. Ann. Se. Nat. x, 360. Seeds and nut- 
lets deeply sulcate or concave on the back, the raphe in the 
hollow: flowers mostly dicecious, solitary or fascicled in the 
axils. 
R. alnifolia L’Her. Sert. Angl. 5. 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 
