Quercus. AMENTACEiE. 5 



They vary in size from two and one half to five centimeters long, and 

 from one to two centimeters hroad. The secondary veins are in a very 

 open angle of divergence from the narrow midrib, often, especially in the 

 small leaves, in right angle to it, curved toward the borders, camptodrome, 

 with primary areas generally divided to the middle by thin tertiary veins. 

 As in the former species, to which it is related by its areolation, the ner- 

 villes in right angle to the secondary veins are divided by cross branches, 

 generally oblique, passing by multiple ramifications into very small areolae, 

 not as distinctly quadrangular as in the former species, but rather irregu- 

 larly polygonal. 



This species is also related to Quercus elceua, Ung., but essentially differs 

 by the form of its shorter leaves. It is more closely allied to the Live 

 Oak, Q. virens ; to the var. nana by its nervation, and to the var. maritima 

 by the form and size of the coriaceous leaves. I have mentioned as Quer- 

 cus virens, from the Pliocene chalk bluffs of the Mississippi, Amer. Journ. 

 of Sci. and Arts, 1859, Vol. XXVII. p. 364, leaves which appear identical 

 with those described here. 



Habitat. — Same locality as the former. Voy's Collection. 



§ II. — Leaves Seeeate or Dentate. 



Quercus Nevadensis, sp. nov. 

 PL II Figs. 3, 4. 



Leaves obovate, rounded to an obtuse point, gradually narroiced from the middle to the 

 base; borders distantly dentate; nervation subcamptodrome. 



We have of this species only the two specimens figured. The length 

 of the leaves is nine to eleven centimeters, and their width from three 

 to five ; their shape is obovate or oblanceolate, as they gradually enlarge 

 upwards from a narrowed base, and are rounded to an obtuse point. The 

 teeth of the borders are distant and short, generally turned outside, sepa- 

 rated by shallow sinuses, and descend to below the middle of the leaves, 

 even, in the small specimen, to near the base. The secondary veins are 

 close, sixteen pairs in each loaf, parallel, mostly simple, passing from the 

 middle nerve, at an angle of divergence of 50°, nearly straight to the 

 borders, where they abruptly curve, entering the teeth by a short branch, 

 a nervation of the same type as that of the dentate leaves of Dryophijllum. 

 The nervilles are very distinct, somewhat distant, mostly simple and de- 



