SHRUBS NOT BECOMING ARBORESCENT. 



As far as kuowu, the following list of shrubs comprises those that 

 rarely, if ever, become arborescent; and the chief object in introducing- 

 them here is to comi)lete, as far as i^ossible, a full enumeration of the 

 woody plants of the region. Plants woody only at the base have been 

 mostly excluded. The annotations added may in some cases assist the 

 reader in recognizing the species. 



BERBERIDACE.E : Barlervics. 



BerbePvIS repexs, Lindl. Oue foot or less iu lieiglit : found tbroughout tlie Eocky 



Mountains, also on tlie Pacific coast; \rood"yellow. 

 Berbekis Fenpleri, Gray. Three to 6 feet: southern Colorado and soutliwaid 



(vs'estward to southern California). 



ZYGOPHYLLACE.E. 



Creosote-bush, Larrea Mexicana, Moric. Four to 10 feet: southern Colorado (to 

 California; also in Texas): slroufj-scented ; foliage cvcrtjreen, dense; llowers 

 yeUow ; fruit beaked. 



Celastrace^e : Staff-tree FamiUj. 



PxiCiiYSTiMA Myijsixites, Kuf. Low j Rocky Mountain region (northward and west- 

 ward); foliage evergreen, forming dense clumps on timbered slopes. 



RiiAMNACEX: Bacldlwrn Family.* 



Bl'Ckthorxs: 



Bhamnus ahtifolia, L'Her. Two to 4 feet : AVyoming (westward and eastward). 



Fruit black, berry-like ; 2 to 4 seeds (nutlets). 

 Ii]iamnu8 CaJiforniea, Escb. Southwestern Colorado and New Mexico (to Cali- 

 fornia and northward to the valley of the ui)per Sacramento Eiver). As 

 it dccurs in the Rocky Mountain region it is a low, spreading shrub (with 

 young branches and under surface of the leaves white-woolly), but in Cali- 

 fornia becoming a small tree 20 to 30 feet high: foliage evergreen; fruit 

 black-purple, with scanty flesh and 2 to 3 seeds. (Introduced among the 

 shrubs, because the Rocky Mountain form is never arborescent. 

 Nev/ Jersey Tea: 



CeanoiJius rchitiniis, Dougl. Two to 3 feet: Colorado, Utah (and northwest- 

 ward): leaves thick, entire, resinous above; often velvety below, Var. 

 kvvigatus, (Torr. & Gray) with leaves mostly smooth below, is commoner 

 than the species. 



Ccanothus ovatus, Desf. Two to 3 feet: Colorado and Wyoming: leaves with 

 small glandular teeth. 



190 



* See arborescent species, page 168. 



