142 



LARAMIE FLORA OF THE DENVER BASIN. 



In the collection from Erie, Colo., there is a 

 smgle example (here figured) which appears to 

 belong with N. tenujolia. It is folded around 

 on both sides of a thin piece of matrix and 

 appears to have been a thin, delicate leaf. Its 

 diameter is about 10 centimeters; it has the 

 same number of ribs as the type specimen. 

 The margin is gently undulate, and the ribs 

 are forked or branched some distance below 

 the margin. The finer nervation is obscure. 



Occurrence: Laramie formation, Erie, Colo., 

 collected by N. L. Britton about 1885. Den- 

 ver formation, Sand Creek, 15 miles east of 

 Denver, Colo., collected by A. Gardner. 



Family MAGNOLIACEAE. 



Magnolia marshalli Knowlton, n. sp. 



Plate XXI, figure 10. 



Magnolia marshalli Knowlton [nomen nudum], U. S. 

 Geol. Survey Bull. 696, p. 374, 1919. 



Leaf oblong-lanceolate, with an obtuse apex 

 and an obtusely wedge-shaped base; midrib 

 straight, thick; secondaries about 15 pairs, 

 alternate or a few subopposite, emerging at an 

 angle of 40° or 45°, running with a slight up- 

 ward curve to a point within one-fifth of their 

 length from the margin, where each arches 

 around and joins the one next above by an even, 

 regular loop, from the outside of which smaller 

 tertiaries are sent toward the margin; nervilles 

 strong, percurrent, at right angles to the sec- 

 ondaries; finer nervation obsolete. 



This fine leaf is 10.5 centimeters long and 

 3.5 centimeters wide at the broadest point, 

 which is perhaps a little above the middle of 

 the leaf. From the broadest point it tapers 

 gradually to a rather obtuse apex and in about 

 the same manner to the base. The petiole is 

 not preserved. The midrib is very thick and 

 prominent. 



This leaf is referred to Magnolia with little 

 hesitation. In outline it is very similar to a 

 number of living species, as, for example, some 

 of the cultivated forms of M. grandiflora 

 Linne, young leaves of M. uinhrella Linne, and 

 particularly M. pealii King, a large tree found 

 in Upper Assam, India. Its relation with M. 

 pealii is very close, indeed, for it has the exact 

 outline — except the taper-pointed apex — and 

 much the same nervation. In nervation M. 

 marshalli has clearly the characters of Mag- 

 nolia, as shown by the figure. 



Among fossil species of the Laramie and 

 post-Laramie formations the present species 

 approaches most closely M. attenuata Lesque- 

 reux,** differing by being much smaller and 

 narrower. It also somewhat resembles M. 

 dayana (Lesquereux) Cockerell, from the au- 

 riferous gravels of California," from which it 

 differs in being only half the size and relatively 

 broader and less wedge-shaped at base. 



Occurrence: Laramie formation, Marshall's 

 mine, Boulder County, Colo., collected by 

 Arthur Lakes, 1890. 



Magnolia lakesii Knowlton, n. sp. 

 Plate XIII, figure 2. 



Magnolia lakesii Rnowlton [nomen nudum], U. S. Geol. 

 Survey Bull. 696, p. 373, 1919. 



Leaf of firm texture, broadly elliptical, 

 almost oval, abruptly rounded in about the 

 same degree to base and apex; margin per- 

 fecth' entire; midrib strong below, becoming 

 much thinner above, straight; secondaries four 

 or five pairs, very thin, opposite or suboppo- 

 site, at a very low angle, much curved upward, 

 each joining the one next above and far inside 

 the margin by a broad loop; nervilles few, 

 mostly unbroken, oblique to the secondaries; 

 finer nervation obsolete. 



The leaf figured, which is one of several of its 

 form, was about 7 centimeters long and 5.5 centi- 

 meters wide. It is nearly elliptical, with an 

 abruptly rounded and truncate base. It is 

 well marked by the thick midrib and few, thin 

 secondaries arising at a very low angle and 

 joining the ones above far from the margin of 

 the blade. 



Among the living American species of the 

 genus Magnolia the leaf under consideration 

 seems to be most closely related to Magnolia 

 acuminata Linne, or more especially its variety 

 cordata, which has been somewhat modified, 

 apparently by long cultivation. The fossil leaf 

 dift'ers in being more nearly elliptical and in 

 having fewer secondaries, but its general 

 appearance is much like that of the species 

 mentioned. 



This species has some resemblance to what 

 was called Ficus haguei Kjiowlton,'" from the 



t The Tertiary flora; U. S. Geol. Survey Terr. Rept., vol. 7, p. 250, pi. 

 45, ng.6, 1878. 



» Harvaril Coll. Mus. Comp. Zoology Mem., vol. 6, pi. 0, fig. 4, 1878. 



1° Knowlton, F. U., Fossil flora ot the YeUowstone National Park: 

 U. S.Geol. Survey Men. 32, pt. 2. pi. 90, flg. 3, 1898. 



