270 



UNIVERSITY OF COLORADO STUDIES 



3a. Leaves ob-ovate in outline; cleft half-way to the mid-rib or less; acorns acute. 



Quercus gambellii Nutt 

 "Gambell's Oak" 



3b. Leaves ob-ovate in outline; cleft deeper than half-way to the mid-rib; acorns obtuse. 



Quercus nitescens Rydb. 

 "Shining Oak" 



Fig. 9. — Shining Oak (Quercus nitescens). X£. 



Genus n. CELTIS, Hackberry 

 These trees have much the appearance of elms. The leaves are 

 oblique at base and the trunk is rough and deeply furrowed. 



ia. Leaves broadly ovate; acute or short pointed at apex; ripe fruit red. 



Celtis reticulata Torr. 

 "Thick-leaved Hackberry" 



lb. Leaves ovate, often long pointed at apex; ripe fruit black. Celtis douglasii Planch. 



"Douglas Hackberry" 



