252 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



described in the Eocene flora of the Mississippi as Asimina leiocarjm, Lesqx. 

 The authority of this determinafiou seems confirmed by tliese leaves, which, 

 however, are of a higher Tertiary group. They are also related to those of 

 Anona lignltum, Ung., and the fruit to that of A. Altenburgensis, Ung. (Sillog., 

 i, pp. 25, 26, pi. X, figs. 1-8), both from the Lignitic formations of Germany. 

 Habitat. — Carbon, Wyoming; shale under the main coal {Dr. F. V. 

 Hayden; Prof. F. B. Meek). I studied it there also in a large number of 

 specimens. 



NYMPHEINE^. 

 NELUMBON^. 



NELUMBIUM, Lmn. 



Few species of this genus live at our time. They are all remarkable 

 by their large, round, peltate leaves, supported by long stalks, and floating on 

 the surface of ponds or lakes. We have still, in the waters of the Ohio and 

 of the Mississippi Rivers, N. luteum, Wild., a species becoming very rare. 

 The leaves are circular, peltate, or borne upon a central petiole, entire, with 

 the nerves placed star-like, numerous, dichotomous in their divisions, and 

 craspedodrome. This generic diagnosis is given here for reference to an 

 anomaly remarked in the nervation of the fossil leaves compared to that of 

 the living ones. 



Three species of Nelumhium are known in the geological times, and 

 described by European authors. 



nrelumbium Lakcsii, Lesqz. 

 Plate XLVI, Figs. 1, 2. 

 Nelumbium LakesH, Lesqx., Annual Kepoit, 1873, p. 403. ' 



Leaves thick, subcoriaceous, subcircular, centrally peltate, entire ; nerves diverging star-like from 

 the center, simple or scarcely branching on one side only; nervilles strong, joining the nerves in right 

 angle, obliquely dividing in the middle. 



These leaves appear to measure about twelve centimeters in diameter; 

 the center is concave, the borders turned down ; all tlie nerves, fourteen, 

 equal in thickness and equally diverging from the center to the circumfer- 

 ence, are deeply impressed and thick, sparingly l)ranching, and, as far as can 

 be seen, only on one side, and not by dichotomous divisions; the surface is 

 rough, deeply furrowed by the nervilles at right angle to the nerves, disjointed 

 in the middle by cross-veinlets. It is scarcely possible to see a difference in 

 the size and in the directions of the nerves, which are more or less turned on 



