112 



PITTOXIA. 



one species, anJ that Q. Jacobi. Tlie lesser tree of the two, 

 with less umbrageous spread of branches, stands close by the 

 north side of a higb building which shuts off the sun so com- 

 l)letely from all the ground around it, that the Ternal develop- 

 ment of leaves and flowers must thereby of necessity be con- 

 siderably retarded. 



Although T noticed many of these oaks in the neitrhborhood 



Q. 



Q 



by Mr. Hansen in his drawing is pretty constant, and although 

 a good mark of the species, there is even a better one in tbe 

 living tree. I refer to the color of the trunks. Q. Garryana 

 is everywhere remarkable for the very light color of its bark ; 

 and this mark holds as perfectly in those northern districts 

 of the Columbia valley and northward, as it does in California. 

 The Q. Jacobi, so far from sharing this characteristic of its 

 ally, is even a shade or two darker than what is seen in the 

 average oak of this group. 



The species is perhaps equally common on the insular and 

 on the mainland shores of Puget's Sound. The precise 



Q 



but 



we may safely say that, if the two species here referred to 

 shall be found growing side by side, in any part of Washing- 

 ton or of British Columbia, they will prove distinguishable 

 at a glance by the different shades of bark on their trunks, as 

 well as by the subpalmate venation of the foliage, and the 



Q 



Q 



Chenes de FAmerique Tropicale, 22 



t. XIV. Hg. 1. it IS a great satisfaction to have seen in the 

 iorrey herbarium, a specimen of Charles Wright's Texan 

 r^o. 6b-A, which Liebmann took for his type of this species. 

 Dr. Engelmann made much confusion of it. He once referred 

 It, as a variety, to the widely different Q. undulata. Some- 

 times he called even the little Arizona Black Oak {Q. Emon/i) 

 Q. pnngens, Liebm." When I discovered the prickly- 

 leaved Arizona variety of Q. clirnsoJems. on th. mnn^l,-.« ..^ 



