FLORA OF TJ3E GREEN RIVER GROUP. 143 



evident relation to JV. dichotoma, Heer, "Fl. Tert. Helv.," i, p. 104, pi. 

 xlviii, ligs. 1-6. Not only the dichotomous disposition of the segments is 

 analogous, but in fig. 1 of Heer the primary division appears as from an 

 obscure innovation, while the top of the main stem seems to be inflated by 

 I he position of apparently fasciculate segments -as they are in the middle 

 of fig. 7 of our plate. The size of the European plant is smaller in all its 

 parts. 



Hob.— Florissant. U. S. Geol. Expl. Dr. F. V. Hayden. 



MUSACEiE. 



MUSOPHYLLUM, Goepp. 

 Mu soph y 11 n in co in pi i cat urn , Lesqx. 

 "U. S. Geol. Rep.," vii, p. 96, pi. xv, figs. 1,6. 



The station of the bed of coal and shale where this plant was found 

 in great profusion, with remains of Sapindus obtusifolius, appears rather 

 referable to the Green River Group than to the Miocene of Carbon from 

 the presence of this last species, which has been found also at Florissant. 



AROIDE^. 



AC0R.US, Linn. 



Acorus hrachystachys, Heer. 

 *'U. S. Geol. Rep.," vii, p. 105, pi. xiv, fig. 16. 



LEMNACE^E. 



LEMNA. Linn. 



Lemna penicillata, sp. nov. 



Plate XXIII, Fig. 8. 



Leaves small, round in outline, irregularly creuulate on the borders; surface 

 rugose; rootlets numerous, in fascicles. 



The leaves, 3 to 4 millimeters in diameter, are rugose on the surface 

 and do not show any trace of nerves; they appear to have been fleshy, but 

 they are quite flattened into thin flakes on soft shales. 



Hal.— Florissant. U. S. Geol. Expl. Dr. F. V. Hayden. 



