214 



Rhamnaceae. 



COLLETIA. 



(Family Rhamnaceae). 



Shrubs, horridly spiny by the 

 decussate branchlets: pith moder- 

 ate, rounded, white, continuous. 

 Buds superposed, the upper at 

 once developing into a spine- 

 branch, the lower minute with 

 about, 2 scales concealed in to- 

 mentum. Leaf-scars lacking, the 

 opposite minute scales which rep- 

 resent the true foliage persistent. 

 Except for a few other species 

 of Colletia, which have slenderer 

 or more rounded spines and are 

 seldom if ever seen in this coun- 

 try, Colletia cruciata, or C. hor- 

 rida as it is called sometimes, re- 

 sembles only the related genus 

 Adolphia of the Southwest, and 

 the rather distantly related Mexi- 

 can Koeberlinia which differs 

 from both in having its spines 



alternately placed and not in the form of a cross. 



Gray-tomentulose, leaf-green when denuded. C. cruciata. 



