98 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



the geological epochs. Scarcely a dozen species have been described by 

 European authors as referable to the first division; the second has about 

 sixty, half of which belong to the genus Potamogeton. 



HYDEOCHAllIDE^. 



OTTELIA, Pers. 

 Ottelia Americaua, Lesqz. 



Plate LXI, Fig. 8. 



OUdia Americana, Lesqx., Annual Eeport, 1874, p. 300. 



Spathe oval, narrowed to a round, striate pedicel, surrounded by an undulate, wrinkled fringe, 

 truncate or emarginato at the top. 



The figured specimen is the only one seen of this species. It represents 

 an oval, tumescent, convex nucleus, the center of a spathe, wrinkled, striate 

 in the length, three and a half centimeters long, seventeen millimeters broad 

 in the middle, narrovs^ed to a thinly striated or veined, half-round pedicel, 

 twelve millimeters long and a little more than two millimeters broad. In the 

 middle of the spathe, the longitudinal striae are thick and deep, irregular, 

 gradually passing toward the base to narrow, parallel lines, which enter the 

 pedicel. This spathe is surrounded by an undulate wing, wrinkled across, 

 eight millimeters broad in the middle, gradually narrowing to the base of the 

 spathe, where it joins the enlarging pedicel. The cross-wrinkles of this wing 

 correspond to the sinuses of the undulations. 



The determination of this fine and remarkable species is due to Count 

 Saporta, to whom I owe the communication of a good figure of Ottelia alis- 

 moides Pers., a living species of Ceylon. The only difference is that, in the 

 living plant, a triphylle calix is persistent at the top of the spathe, while in 

 ours its place is occupied by part of the wing, which possibly represents a 

 flattened calix. No fragments of any other organs of this species have been 

 discovered. Leaves of one species of this genus have been described by 

 Saporta from the Calcaire grassier (Middle Eocene) of Paris. 



Habitat. — Point of Rocks (J)r. F. V. Hayden). 



POTAME^. 

 NAJADEJE. 



CAULINITES, Brgt., Ung. 



Stems branching, striate, marked by sublunar and round scars; leaves flat, doubly striate; 

 rbizomas piano-articulate, with double, irregularly round scars of branches, or warts and dots, marking 

 points of attachment of radicular lilaments. 



This genus is slightly modified, according to the characters of the frag- 



