102 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



nilic. But in this the nutlets are hard, compact, all of the same form, the 

 young and the old ones, and thus unlike sporanges of Ferns. The analogy 

 seems rather to be with the species described and figured as Leptomeria gra- 

 cilis, Ett. (Foss. Fl. V. Hilr., pi. xiii, fig. 5). 



Habitat — Erie, Colorado, sandy shale above main coal. 



FLUYIALES. 



LEMNACEJil. 



Liemna scutata, Daws. 



Plate LXI, Figs. 2, 5. 



Zemna scuiata, Daws., Rep. on the Geol. of the 9th Parallel, Appendix A, p. 329, pi. xvi, figs. 5, 6.— Lesqx., 

 Annual Report, 1874, p. 300. 



Frond round, entire, slightly undulate on the edges, single or grouped; roots nnmerons, filiform, 

 proceeding from a round spot near the notch of the frond. 



The fronds of this species, as represented in our figure, are eight to 

 twenty-five millimeters broad, exactly round in outline, either and more 

 generally naked, without radicles, or bearing a fascicle of filiform very slender 

 rootlets from a narrowed base resembling a short pedicel. Those without 

 radicles (as in fig. 2) show the basilar (I) part in the center of the frond, 

 and thus resemble a llattened vesicular plant. In both figures, distinct 

 veins are seen passing up from the short pedicel, or, as in fig. 2, diverging 

 around from the center. Comparing them with those of the author's, the 

 similarity of shape of the fronds is striking, but the fronds figured from 

 Canada have scarcely any trace of veinlets, a few only being indistinctly 

 marked in fig. 5 {loc. cit.), and the fiiscicles of radicles are attached, it seems, 

 to the borders without any pedicel. From the observation of Prof. G. M. 

 Dawson, who collected the specimens, this species is found upon shale break- 

 ing very easily, and no sufficient representation could be obtained of the spe- 

 cies, though its remains were plentiful. As remarked by the author, it "is asso- 

 ciated ivith great quantities of roots and rootlets of filiform, subaquatic leaves''\ 

 and our specimens are in the same way intermixed to a mass of radicles, so 

 thickly interwoven that it is not possible to precisely see their points of con- 

 nection to the numerous fronds mixed with or deposited upon the tissue. 

 Each frond, however, when considered separately upon detached fragments, 

 looks as if it was completely surrounded by rootlets connected to or depend- 



