FLOEA OF THE DAKOTA GEOUP. 41 



texture of the leaf and its smooth surface do not contradict this reference; 

 for all the species of willows of the Dakota Group are coriaceous, as are 

 generally the willows of the tropical or warm regions. 

 Hah. — Blackbird Hill, Nebraska. Dr. Hayden. 



Quercus cuneata, Newby. 



" Notes on Ext. ¥\.," p. 25. 



Leaves short, petiolate, lanceolate, pointed at both ends, acute, entire, or slightly 

 Avave-margined ; midrib strong ; secondary veins remote, nearly straight, with short 

 intermediate ones; surface smooth, texture originally thick and coriaceous. (Ny.) 



The author compares this species to Q. imhricaria, Michx., for the 

 form and consistence of the leaves. 



Hab. — Blackbird Hills, Nebraska. Dr. Hayden. 



Quercus antiqua, Newby. 

 "Notes on Ext. Fl.," p. 26. 



Leaves of medium size, lanceolate in outline, acute, often somewhat flexuous^ 

 margins serrate-dentate, with strong obtuse teeth, which are appressed or turned 

 upward; midrib strong, percurrent; secondary veins numerous, of unequal strength^ 

 arched upward, craspedodrome. (Ny.) 



Hah. — Lower Cretaceous sandstone, Banks of the Rio Dolores, Utah. 



Quercus sinuata, Newby. 



" Notes on Ext. FJ.," p. 27. 



Leaves small, ovate in general outline, narrowed to the petiole or slightly decur- 

 rent; margins deeply lobed; lobes rounded, broader than the sinuses that separate 

 them, three, nearly equal on either side; summit broadly rounded or obscurely lobed, 

 often oblique; midrib straight or slightly flexed; secondary veins strong and simple, 

 running to the margin of each lateral lobe. (Ny.) 



The author compares the species to the living Q. obtusiloba, Michx. 



Hah. — Same as the preceding. 



SALICINEiE. 



SAIIX, Toum. 



Salix nervillosa, Heer. 



" PhyU. Cr6t. du Neb.," p. 15, pi. i, fig. 3. 



Leaves oblong, lanceolate, very entire; secondary veins in an acute angle of 

 divergence, curved, camptodrome; nervilles curved, at right angles to the midrib. 



Hah. — Nebraska. Dr. Capellini. 



