NO. 2151. FOSSIL PLANTS FROM FLORISSANT— KNOWLTON. 251 



The only other grass described from Florissant is Stipa laminarum 

 Cockerell,^ based on isolated long-awned grains similar to those of the 

 ^YUigStipa connata Trinius and Rupricht. The grain is said to be 10- 

 11 mm. long and about 2 mm. broad, while the awn is ''quite 60 mm." 

 long. It is obviously very distinct from the species here described. 



Family TYPHACEAE. 



TYPHA LESQUEREUXI Cockerell. 



Typha lesquereuxi Cockerell, Bull. Torr. Bot. Club, vol. 33, 1906, p. 307. 

 Typha latissima Al. Braun. Lesquereux, Rept. U. S. Geol. Siirv. Terr., vol. 8 



(Cret. and Tert. Fl.), 1883, p. 141, pi. 23, figs. 4, 4a. [Not T. latissima Al. 



Braun.] 



A single characteristic example showing the complete apical por- 

 tion of a leaf; from the Scudder collection. 



Family POTAMOGETONACEAE? 

 PALAEOPOTAMOGETON, new genus. 



PALAEOPOTAMOGETON FLORISSANTI, new species. 



Plate 16, fig. 1; plate 17, fig. 3. 



Stems slender, erect, weak, possibly aquatic ; leaves opposite, short, 

 grass-Uke, acuminate at apex, probably sheathing at the base, nervation 

 obscure, a midrib only discernible; fruit borne on long, slender almost 

 filiform, axillary peduncles, the fruits spheroid, short-pediceled, 

 apparently indehiscent. 



Types.— Cat. Nos. 34,748, 34,749, U.S.N.M. 



This form is represented by the two specimens figured and by a 

 nimiber of isolated fruits. With the exception of the fruits, they are 

 very faintly impressed on the matrix, as though the stems were soft 

 and weak, suggesting an aquatic habitat. The best preserved speci- 

 men (fig. 1), representing the upper portion of a stem now about 

 11 cm. in length, which bears at the apex a number of leaves that are 

 apparently broader than the other leaves and suggest the possibihty 

 that they were floating. 



The fruits, as already pointed out, are the most definite parts pre- 

 served. They are spheroid or ovoid, about 2 mm. in diameter, and 

 evidently had a very hard ''shell" or test. There is evidence of the 

 presence of rather strong ridges, but nothing to indicate that they 

 were dehiscent, in fact they suggest akenes rather than capsules. 

 Each fruit is short-pediceled and borne on a long, slender, axillary 

 pedimcle. The peduncles are clearly alternate, but this is probably 

 an incident rather than a point of significance. 



'Cockerell, T. D. A., Bull. Amer. Mus. Nat. Hist., vol. 24, 1908, p. 79, pi. 6, flgs. 1, 3. 



