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ZYGGPHYLLACEAE. 



COVILLEA. Creosote 'Bush. 

 (Family Zygophyllaceae). 



Odoriferous small shrubs exud- 

 ing balsam where wounded: ever- 

 green. Twigs 4-angled, becoming 

 round in age, with short inter- 

 nodes: pith 4-sided, continuous. 

 Buds solitary, sessile, small, ovoid, 

 with 2 scales, usually imbedded 

 in " balsam. Leaf-scars opposite, 

 somewhat raised, minute, round: 

 bundle-trace 1 1, usually, like the 

 outline of the scar, concealed by 

 the exudation: stipules relatively 

 large, brown, persistent. Leaves 

 short-stalked, of 2 falcate more or 

 less parallel leaflets. Fruit, when 

 present, long-hairy capsules, 

 (Larrea). 



Few plants are more character- 

 istic of the dry country than the 

 creosote bush or, as it is called 

 often though improperly, grease- 

 wood, and none is more readily recognized at sight. As in 

 lignum vitae, the evident persistent stipules give it a dis- 

 tinctive character. In an account of the native trees and 

 shrubs published as Bulletin 87 of the New Mexico Agricul- 

 tural Experiment Station, Wooton speaks of the characteris- 

 tic bright color of Covillea in contrast with the prevailing 

 gray of other vegetation. 

 Twigs at first green, puberulent. C. tridentata. 



