ENGELMANN OAKS OF THE UNITED STATES. 3S7 



The suggestion that the character of vernation would be an 

 important assistance in classification, and in the discovery of alli- 

 ances of hybrids, has been verified by actual observation, as will 

 be shown below. 



Page 376. The glandular colored pubescence appears on both 

 sides of the voung leaves in Catesbcei^ sinuata and myrti folia ; 

 on the lower side in chrysolepis and somewhat in stellata ; on 

 the upper side 'vi\ falcata^ and also in Catesbcei-laurifolia. I do 

 not find this pubescence on seedlings of these species, nor is it 

 often seen on the youngest leaves, but becomes developed when 

 the leaf has attained i to J of its full size. 



The reticulation is generally more marked on the upper than 

 on the lower side of the leaves, and in the Black-oaks more than 

 in the White-oaks : an exception occurs in J^. falcata and (as 

 already indicated) agrifolia; in both the upper surface is s^lmost 

 smooth ; in cinerea and ilicifolia the reticulation is much less 

 prominent than in most others. 



Pag. 377. The male aments are produced from scaly buds 

 which are not further developed, or from the lower part of 

 branchlets, usually in the axils of budscales, or rarely from the 

 axils of the lowest leaves; thus often in ^. agrifolia. They are 

 mostly simple, but in chrysolepis I find them often branching, 

 such as they are described in the Asiatic section Pasania. 



Pag. 378, 1. 16 and 17, strike out the comma after "connected," 

 ^'differences" and "petiole." Add in before "the shape." 



L. 33. Fottr Black-oaks with annual maturation, including 

 ^. Emoryi. 



Pag. 379, 1- 22. Occasionally Black-oaks are found with cup- 

 scales thickened at base ; Prof. Sargent has collected near Cam- 

 bridge fruits of ilicifolia with this peculiarity, and it does not 

 seem to be rare at all in northern forms of rubra. 



L. 6 from below. The abortive ovules are not oval and pendu- 

 lous, but rather bottle-shaped bodies, suberect in the White-oaks, 

 hemitropous in the Black-oaks. 



Pag. 380, 1. V ^. Emoryi.^ in every other respect a true Black- 

 oak with annual fructification, has basal ovules, another remark- 

 able instance of mere botanical characters not always coinciding 

 with essential ones. Hence the word " always," in the first sen- 

 tence of the following page, must be qualified by adding almost. 



