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UNIVERSITY OF COLORADO STUDIES 



Fig. 20. — Choke Cherry (Prunus melanocarpa). X J. 



Genus 16. ROBINIA, Locust 

 The native Colorado locust is closely related to the common black 

 locust or yellow locust now so often planted for posts and railway ties. 



1 a. Small tree or shrub with pinnately compound leaves and pink, pea-like flowers, pro- 

 Gray. 



ducing many-seeded pods. 



Along streams in southern part of state. 



Robinia neo-mexicana A. 

 " Pink Locust." 



Genus 17. ACER, Maples and Box-Elder 



ia. Leaves compound, of 3, 5 or 7 leaflets. Acer interior Britt. 



"Box-Elder" 



lb. Leaves simple; palmately veined. (2) 



2a. Leaves longer than broad; generally three-lobed, margins distinctly serrate. 



Acer glabrum Torr. 

 "Rocky Mountain Maple" 



2b. Leaves broader than long; three to five-lobed; margins not serrate. 



Acer grandidentatum Nutt. 

 "Mountain Sugar Maple" 



