DESCltirTION OF SrECIES— HALOKAGE^. 295 



CALYCIFLORiE. 

 UALOUAGE^. 



TRAPA, Linn. 

 T I' ii p :■ ! Ill i c ■■ oi> li y 1 1 n , Lesqz. 

 I'lato LXI, Figs. 1(J-17 a. 

 Trapaf microphyVa, Lesqx., Anunal Heiiort, 1874, p. 301. 



Leavi'H Rinall, round or broadly ovnl aud obtuse, roiindf d to the petiole ; borders denticulate from 

 below the middle upward; nervation ternate from the top of the petiole, or irregularly pinnate; lateml 

 veins at an acute angle of divergence, 15° to 20°, flexuous, with dichotomoua branches, all cra»pedo- 

 drorae ; areolation distinct, polygonal, minute, by subdivisions of the veinlets at right angle. 



These leaves, represented in nunnerous specimens, vary in size from a 

 little more than one centimeter long, and nearly as large, to about two and a 

 half centimeters long and nearly two broad. They are generally oval, very- 

 obtuse, and somewhat enlarged upward; the borders are minutely dentate 

 e.xcept at or near the base, rounded to a comparatively long and slender peti- 

 ole, the only one of tlie leaves where it is preserved, not even to its base, 

 being eighteen millimefers long and the petiole nine millimeters. The are- 

 olation is clearly defined, in very small square or polygonal meshes, formed 

 by close, thick nervilles anastomosing with veinlets parallel to the nerves and 

 their divisions, Ihe parietes being as thick as the veins. The same kind of 

 nervation is observable upon the lower surface of the leaves of the living 

 TrajMi natans, Linn., which, though comparable to these fossil ones, liave the 

 borders deeply toothed, and are of a much thicker texture. In this species, 

 the leaves appear as meml)ranaceous and pellucid, for the nervation and are- 

 olation seem as drawn in black upon the yellowish substance of the laminae. 



No fossil leaves published as yet are to my knowledge comparable to 

 these, except those described by Prof Newberry, in llie Report of the Col- 

 orado Exploring Expedition by Lieut. J. C. Ives, p. 131, pi. iii, fig. 5, under 

 the name of Neuropieris angulata. The general form of the slightly dentate 

 leaves and the remarkably acute angle of divergence of the secondary nerves 

 are the same; even the irregular, though too obscurely marked, divisions of 

 the lateral veins seem to be of the same character. It may be remarked, as 

 a kind of confirmation of the reference of these leaves to Traiia, that Prof. 

 J. W. Dawson lias observed aii<l described a iVuit ol' this genus, found in 

 connection with his Lemna scutata, (Voui deposits identical by lithological 

 characters and geological station jo those of Point of Rocks. 



Habitat. — Lower Eocene stralti oi" llic Ligiiitic at Point of Rocks, 

 Wyoming {Vr. F. V. Hoyden); also seen upon IIk: sjx'cimens communicated 

 iVom Ihc same locality l>y J//'. \Vm. Cleburn. 



