DESCEIPTION OF SPECIES— HALOKAGE^. 295 



CALYCIFLOR^. 

 nALORAGE^. 



TRAPA, Linn. 

 T r a p a ? in i c r op li y 1 1 a , Lesqz. 



Plate LXI, Figs. 16-17 o. 

 Tiapa? microphyVa, Lesqx., Auuual Report, 1874, p. 304. 



Leaves sraall, round or broadly oval and obtuse, rounded to the petiole ; borders denticulate from 

 below the middle upward ; nervation teruate from the top of the petiole, or irregularly pinnate ; lateral 

 veins at au acute angle of divergence, 15° to 20°, flexuous, with dichotomous branches, all craspedo- 

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



These leaves, represented in numerous 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 

 except at or near the base, rounded to a comparatively long and slender peti- 

 ole, the only one of the leaves where it i.s preserved, not even to its base, 

 being eighteen millimeters long and the petiole nine milHmeters. 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, the parietes being as thick as the veins. The same kind of 

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

 Trnpa natans, Linn., which, though comparable to these fossil ones, have the 

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

 the leaves appear as membranaceous and pellucid, for the nervation and are- 

 olation seem as drawn in l)lack upon the yellowisli substance of the laminae. 



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

 these, except thos6 described by Prof Newberry, in the Report of the Col- 

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

 the name oi Neuropteris 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 Trapa^ that Prof. 

 J. W. Daw .son has observed and described a fruit of this genus, found in 

 connection with liis Lemna scutata, from deposits identical by lithological 

 characters and geological station to those of Point of Rocks. 



Habitat. — Lower Eocene strata of the Lignitic at Point of Rocks, 

 Wyoming {Dr. F. V. Hayden); also seen upon the specimens communicated 

 irom the same locality by Mr. \Vm. Clebarn. 



