124 



LARAMIE FLORA OP THE DENVER BASIN. 



Occurrence: Laramie formation; Popes Bluff, 

 just west of Pikeview, Colo. (sec. 14, T. 13 S., 

 R. 67 W.), collected by A. C. Peale and M. I. 

 Goldman, 1908. 



Myrica oblongifolia Knowlton, n. sp. 



Plate XXI, figure 1. 



Myrica oblongifolia Knowlton [rtomen nudum], U. S. Geo!. 

 Survey Bull. 696, p. 396, 1919. 



Leaves membranaceous, long-elliptical, 

 rounded to a slightly wedge-shaped base and 

 to an obtuse apex; margin with numerous 

 small, sharp teeth for the lower two-thirds, 

 thence undulate and nearly entire to the apex; 

 nervation paryphodrome, with a slender mar- 

 ginal nerve around the leaf 1 millimeter from 

 the border; slender nerves from the outside of 

 this intramarginal nerve appear to enter the 

 teeth; nerves very numerous, yet at an acute 

 angle, irregular and broken, often joining, end- 

 ing when they reach the border, in the intra- 

 marginal vein ; nervilles usually percurrent. 



This species is based upon the single fine 

 specimen figured. It is about 8.5 centimeters 

 long and 4 centimeters broad, with a petiole 0.5 

 centimeter long. It is a broad, long-elliptical 

 leaf which is about equally rounded to both 

 base and apex. The teeth begin within 1 centi- 

 meter of the base, and are fine, sharp-pointed, 

 and directed toward the apex. In the upper 

 portion of the blade the teeth are reduced to 

 mere undulations, and at the apex the margin 

 is nearly entire. 



The most pronounced characteristic of this 

 leaf is the strongly marked paryphodrome 

 nervation — that is, a thin intramarginal nerve 

 extending all around the leaf about 1 milli- 

 meter distant from the margin. The other 

 nerves, or secondaries, if they may be so called, 

 are very numerous, at a low angle of divergence, 

 and much broken and irregularly joined. 



It is difficult to determine the genus to which 

 this leaf should be referred. There are a num- 

 ber of living genera that have this peculiar 

 paryphodrome nervation, as, for example, Tris- 

 tania of the family Myrtaceae, Ardisia of the 

 Myrsinaceae, and Dodonaea of the Sapinda- 

 ceae, as well as many others less likely to be 

 represented in a fo9sil state. On the whole it 

 appears best to refer it to Myrica because it 

 agrees in this character with many living spe- 

 cies of the genus — for example, M. terebiuttacea 

 Goppert, from tropical America, and Myrica 



sp. from Brazil — and also because it is evi- 

 dently allied to Myrica torreyi Lesquereux, a 

 fossil species of wide vertical range which is 

 also found in the Laramie. Myrica torreyi 

 is undoubtedly the nearest relative of M. 

 oblongifolia that has not been described from 

 material collected in this area. It differs, how- 

 ever, in being narrowly lanceolate instead of 

 broadly oblong and in being linear-acuminate 

 instead of obtuse. The teeth in M. torreyi are 

 larger and more distant. 



This new species does not appear to be 

 closely related to any of the other fossil Ameri- 

 ican species of Myrica. It has much the shape 

 and marginal dentation of Oelastrophyllum de- 

 currens Lesquereux, from the Dakota sand- 

 stone, but that species differs absolutely in the 

 nervation. Myrica oblongifolia is also in out- 

 line and serration like the figures of Quercus 

 Jvaidingeri Ettingshausen given by Lesque- 

 reux, 69 but that species also differs in nervation. 



Occurrence: Laramie formation, Marshall 

 mine, Marshall, Boulder County, Colo. 



Order SAMCALES. 



Family SALICACEAE. 



Salix myricoides Knowlton, n. sp. 



Plate IV, figure 7. 



Salix myricoides Knowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 569, 1919. 



Leaf linear-lanceolate, with a very long, 

 slenderly acuminate apex and an apparently 

 rather obtusely wedge-shaped base; margin 

 entire; midrib relatively very thick; secon- 

 daries very numerous, probably about 20 pairs, 

 approximately at right angles to the midrib, 

 each joining the one next above by a broad 

 loop just inside the margin; finer nervation 

 obsolete. 



The only example of this characteristic spe- 

 cies observed is the one here figured. It is 

 about 8 centimeters in length and 1 centimeter 

 in maximum width; this width holds for more 

 than half the length of the leaf. The leaf 

 appears to have been rather thick, and as it is 

 the upper side that is exposed, the nervation 

 is obscured, all that can be made out being' the 

 very thick midrib and the numerous close, par- 

 allel secondaries nearly at right angles to it. 



ra Lesquereux, Leo, U. S. Geol. Survey Terr. Kept., vol. 7, p. 156, 

 pi. 20, figs. 9, 10, 1878. 



