KNOWLTON.] PLANTS OF THE PAYETTE FORMATION. 725 



POPULUS LINDGRENI n. Sp. 

 PL C, fig. 3. 



Leaf of firm texture, coriaceous, nearly circular in outline, being 

 only a trifle broader below the middle, whence it is rounded to a trun- 

 cate base, and above to a very obtuse apex; margin somewhat irreg- 

 ularly but finely crenate-toothed, the teeth obtuse; petiole over 2 cm 

 in length, very large, flattened; palmately five-nerved or ribbed from 

 the top of the petiole, the central or midrib strongest, very thick, 

 the two lateral ribs also strong, the lowest pair being the slightest; 

 the central or midrib with two pairs of subopposite secondaries high 

 above the middle ; the large lateral pairs of ribs each with about six 

 secondaries on the outside, emerging at a very low angle and arch 

 ing near the margin ; finer nervation obscure. 



The fine specimen figured is the only one obtained of this charac- 

 teristic species. It is nearly circular in outline, being 5.25 cm in length 

 without the petiole, and nearly 5.5 cm in width at the broadest portion, 

 which is just below the middle. The petiole is a little more than 2 cm 

 in length, 2 mm in width as it emerges from the base of the leaf, and 

 3.5 mm in width at the other end. It appears to be preserved entire 

 and is clearly flattened. 



The margin of the leaf is closely crenate-toothed, the teeth being 

 obtuse. The nervation is markedly five-ribbed from near the top of 

 the petiole, the three central ribs being by far the stronger. The 

 lowest lateral ribs or nerves are small and soon lost in the blade of 

 the leaf. 



Among living species this appears to approach most closely to P. 

 balsamifera candicans. It differs in being much more obtuse, in 

 having a more marked crenate border, and in the stronger nervation. 

 The relationship is, however, quite marked, the two leaves being of 

 the same type, but with strong specific differences. 



There is no fossil American species with which this is to be closely 

 compared. There are several with approximately the same shape, 

 yet differing clearly in serration, nervation, etc. 



I take pleasure in naming it after Mr. Waldemar Lindgren, of the 

 United States Geological Survey. 



Locality: Two miles southeast of Marsh post-office, Boise County, 

 Idaho. 



POPULUS EOTREMULOIDES n. Sp. 

 PI. C, figs. 1, 2; CI, figs. 1, 2. 



Leaves membranaceous yet firm-textured, broadly ovate in outline, 

 rounded regularly to the base and contracted above to an obtusely 

 acuminate apex; margin entire for lower fourth of leaf, remainder 

 obscurely crenate-toothed ; petiole very long, flattened; midrib rather 



