ENGELMANN OAKS OF THE UNITED STATES. 543 



young trees or shoots of nigra have sinuate-dentate or many- 

 lobed leaves, but in fertile ones the leaves are almost always 

 more or less 3-lobed or 3-dentate at the much-widened apex. I 

 have since seen a tree which on one fruit-bearing branch had only 

 the leaves of qtdnqucloba, while all the other branches had the 

 regular cuneate 3-dentate nigra leaves. The same form occurs 

 near Washington, L. ~F. Hard, in "Field and Forest," October, 

 1S75, where several other real or supposed hybrids are enumer- 

 ated, which call for further careful investigation in loco. 



ADDITIONAL NOTES. 



New material having come to hand since the above was in type, I have 

 to add some further remarks. 



The typical «£>. ■ palustris has globose or depressed acorns, but near 

 St. Louis it is occasionally seen with oblong or even elongated acorns. A 

 specimen of Q. Texana, Buckley, sent bythe author to the Agricultural 

 Department, Washington, is evidently this form of palustris, though it is 

 said to grow near Austin "on hills." 



Pag. 394. Another abnormal type, which I cannot but refer to rubra, 

 has been sent from the bottom lands of the Comale and Blanco rivers, 

 affluents of the Guadalupe, Texas, by Lindheimer and Wright. The leaves 

 have the cut of coccinea; the large (1 inch long by less than § wide) oblong 

 acorns are borne in hemispherical slightly turbinate cups, covered by 

 small, appressed, smoothish scales. The bark of the tree is "pale and 

 smoothish, much like that of aquatica.'" In many respects the tree seems 

 to be intermediate between rubra and coccinea, an "ambiguous" form. 



«^>. coccinea : numerous specimens, fresh ones from this neighborhood, 

 and dried ones with mature fruit from different localities, have weakened 

 my hope of distinguishing tit.ctoria from the typical coccinea. The yel- 

 lowish-canescent, squarrose cup scales are found in all the forms of this 

 region, but northward as well as eastward they do not seem to be so cha- 

 racteristic of the species ; there they are often smaller, more appressed, 

 and less canescent; and this may be the form which Michaux has figured 

 as his coccinea, while his tinctoria has larger and paler scales. We may, 

 then, distinguish the following varieties: 1. Large winter buds, leaves 

 with broader undivided lobes, cup scales squarrose, acorns oblong or glo- 

 bose. 2. Small winter buds; leaves with slender, deeply cut, divaricate 

 lobes, cup scales and acorns as in 1. 3. Buds and leaves as in 2 ; cup scales 

 smaller, more glabrate, appressed ; acorns more commonly ovoid. 



The first may be Bartram's ^_. tinctoria, the third the true coccinea, and 

 the second an intermediate form. The third variety closely approaches 

 what I have considered as the form ambigua of Q. rubra. 



