106 DUDLEY MEMORIAL VOLUME 



oblong, erect or drooping, maturing in one season; scales 8-12, the middle 

 2 or 3 pairs fertile. 



Four species are recognized in this genus, two in North America and two 

 in Asia. 

 Cones pendulous ; scales thin, with a minute mucro. 



1. T. plicata. 

 Cones erect ; scales angled on the back, with a stout, recurved dorsal hook. 



2. T. orientalis. 



1. Thuya plicata Don. Western Red Cedar. 



Leaves bright green and glossy above, dark green beneath, with whitish 

 triangular markings; cones cylindric-ovoid, scarcely over l / 2 inch long; 

 scales 8-10, elliptic-oblong, usually the 3 middle pairs fertile; seeds com- 

 pressed, notched at the apex, with 2 narrow wings. 



A large forest tree, 200 feet high, with short horizontal branches often 

 with pendulous tips. Native of northwestern America, extending from 

 Alaska to northern California. A specimen is in the eastern part of Encina 

 Garden and another is near Mausoleum Avenue. 



2. Thuya orientalis L. Arborvitae. 



Leaves acute, bright green, with a small dorsal gland; cones erect, 

 globose-ovate, ^4 mcn l n gj scales usually 6, oval; angled on the back, and 

 with a dorsal horn-like process, the uppermost pair sterile; seeds wingless. 



Pyramidal trees 25 feet high or bushy. Native of Persia and extending 

 to eastern Asia. There are many garden forms of this extensively cultivated 

 species. Abundantly planted on the University grounds. 



12. Cupressus. 



Evergreen trees or rarely shrubs. Leaves decussately opposite, ap- 

 pressed, small, scale-like. Flowers monoecious, very small, terminating short 

 branchlets. Cones globose or nearly so, consisting of 3-7 pairs of peltate 

 woody scales, each bearing many seeds, maturing the second year. 

 Branchlets terete or quadrangular, not forming flat spays. 

 Leaves glandless or with an obscure dorsal gland. 



Branchlets erect or spreading, the ultimate rather short and stout. 

 Ultimate branchlets terete or nearly so ; cones usually 1 ^4 inch long 



or more. 1. C. sempervirens. 



Ultimate branchlets 4-sided; cones globose, 1 inch or less broad. 

 Staminate cones subglobose, with 2 lateral anthers in each row ; 

 seeds dull grayish or blackish brown. 



2. C. macro car pa. 



