RHAMNACE^E. (BUCKTHORN FAMILY.) 47 



§ 2 Seeds and nutlets convex on the back : flowers mostly perfect, in pedunculate 

 cymes. — Frangula. 



2. R. Caroliniana, Walter. Thornless shrub or small tree: leaves 

 oblong, obsaurely seirulate, deciduous : flowers in one form umbelled, in another 

 solitary in the axils : fruit globose, 3-seeded. — Frangula Caroliniana, Gray. 

 From the mountains eastward across the continent. 



3. R. Califomiea, Esch. A spreading shrub, with the young branches 

 somewhat tomentose : leaves ovate-oblong to elliptical, denticulate or nearly entire, 

 evergreen : peduncles with numerous mostly abortive flowers in subumbell ate fascicles : 

 fruit blackish purple with thin pulp, 2 to 3-lobed and 2 to 3-seeded. — Frangula 

 Califomiea, Gray. S. W. Colorado to California. 



4. R. Purshiana, DC. Sometimes 20 feet high ; young branches tomen- 

 bose : leaves elliptic, denticulate, deciduous, somewhat pubescent beneath : flowers 

 rather large, in a somewhat umbellate cyme : fruit black, broadly obovoid, 3-lobed 

 and 3-seeded. — N. Idaho and westward in the Pacific States. 



2. CEANOTHUS, L. New Jersey Tea. 



Flowers perfect. Calyx 5-cleft. — Shrubs or small trees, sometimes spines- 

 cent, with petioled leaves and showy thyrsoid or cymose white (in ours) 

 flowers. — Watson, Proc. Am. Acad. x. 333. Ours all belong to the first sec- 

 tion of the genus, in which the leaves are all alternate and 3-nerved, glandular- 

 toothed or entire, and the fruit not crested. 



* Branches not spiny : inflorescence thyrsoid : leaves usually large, 

 glandular-serrate. 



1. C. velutinus, Dougl. A shrub 2 to 3 feet high, usually glabrous : 

 leaves thick, broadly ovate or elliptical, resinous and shining above, sometimes 

 velvety beneath : flowers in a loose thyrse : peduncles usually short. — Colorado, 

 Utah, and northwestward. 



Var. lssvigatus, Torr. & Gray. Leaves mostly glabrous beneath. — More 

 common than the type ; ranging from Colorado northwestward to the British 

 boundary. 



2. C. OVatUS, Desf. A shrub 2 to 3 feet high : leaves narrowly oblong or 

 elliptical-lanceolate, glandular-serrulate, nearly glabrous : thyrse umbel-like> 

 the pedicels elongated and closely approximated. — Includes C. ovalis, Bigel. 

 Colorado and Wyoming. 



3. C. sanguineus, Pursh. A shrub 4 to 12 feet high: stem and branches 

 reddish : leaves broadly ovate or nbovate, subcordate, serrate : thyrsoid corymbs 

 in lateral panicles, on very short peduncles. — Includes C. Oreganus, Nutt. 

 Along the Missouri and its tributaries. 



* * Branches mostly spinosi, grayish : flowers in simple clusters : leaves 

 small, entire. 



4. C. Pendleri, Gray- A shrub one or two feet high, widely and intri- 

 cately branched : leaves oval or elliptic, silky-canescent beneath, smoothish 

 and green above • flowers in clusters, dense, sessile, glabrous. — Colorado and 

 southward. 



