SHRUBS NOT BECOMING ARBORESCENT. 



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

 rarely, if ever, become arborescent; and thechief object in introducing 

 them here is to complete, as far as possible, 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. 



Berbkridace.e : Barberries. 



Berberis repens, Lindl. One foot or less in height : found throughout the Rocky 



Mountains, also on the Pacific coast; wood yellow. 

 Berberis Fendleri, Gray. Three to 6 feet: southern Colorado and southward 



(westward to southern California). 



ZYGOPTIYLLACEiE. 



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

 California; also in Texas): sirong-scented ; foliage cvergrreew, dense ; llowers 

 yellow ; fruit beaked. 



CELASTRACEiE : Staff-tree Family. 



Pachystima Myrsinites, Raf. Low ; Rocky Mountain region (northward and west- 

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



RiiamnacEyE: Buclctliorn Family.* 



Buckthorns : 



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



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

 Bhamnus Californica, Esch. Southwestern Colorado and New Mexico (to Cali- 

 fornia and northward to the valley of the upper Sacramento River). As 

 it occurs 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, "i 

 New Jersey Tea : 



Ceanothus velutinus, Dougl. Two to 3 feet: Colorado, Utah (and northwest- 

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

 Iwvigatus, (Ton. & Gray) with leaves mostly smooth below, is commoner 

 than the species. 

 Ceanothus ovaiiis, Desf. Two to 3 feet: Colorado and Wyoming: leaves with 

 small glandular teeth. 



* See arborescent species, page 168. 

 190 



