92 THE LATER EXTINCT FLORAS OF NORTH AMERICA. 



Cabomba ineemis (Newb.) Hollick. 



PL XXII. fig. 2; XXIII, fig. 2. 



Psilotum inerme, Newb. Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 1868), p. 38; 

 Ills. Cret. and Tert. PL (1878), PL VII, fig. 2, under "aquatic rootlets of 

 Equisetum " ; VIII, fig. 3, under Psilotum inerme. 



Associated with the last -described species are a large number of 

 dichotomously forked, flattened leaves, which are imperfectly represented 

 in the figure given. These have all the general character of the smaller 

 ones, but are many times larger — 5 to 6 inches in length — so large, indeed, 

 that it seems impossible that they should have appertained to the same 

 species. A distinct and significant name has therefore been given to them. 1 

 These leaves are flattened and smooth, and have precisely the aspect of the 

 broader leaves of the living Cabomba. Groups of these springing from a 

 common base were formerly likened to Psilotum, and described in the Later 

 Extinct Floras as P. inerme; but the study of additional material has led 

 to the conviction that the probabilities are very much stronger that we have 

 here a representation of a species of Cabomba. The isolated position of 

 Cabomba in our modern flora is an indication that it is a relic of the past, 

 and it was to be expected that in the sediments of the ancient fresh-water 

 lakes of the far West, where the leaves of palms are preserved, affording 

 evidence of a warm climate like that of our Southern States, traces of the 

 former existence of Cabomba should be found. With some of the groups 

 of leaves of the plant now under consideration are imperfect traces of 

 fructification which in their general character confirm the reference to 

 Cabomba, and yet are not sufficiently well preserved to thoroughly estab- 

 lish the botanical affinities of these plants. It is to be hoped that attention 

 being called to this peculiar group of fossils, they will be specially sought 

 and found in the Fort Union beds in such condition as to establish beyond 

 question their botanical affinities. 



In fig. 2, PL XXII, a pair of leaves is represented which are interme- 

 diate in size between the two forms described, and these are erroneously 

 shaded in such a way as to give the impression of rounded stems; in fact, 

 these leaves are perfectly flat and correspond in form and structure to the 



1 Dr. Newberry's manuscript name for this species is C. grandis, but under the accepted 

 rules of nomenclature the original published specific name inerme must stand. — A. H. 



