NO. 2270. MIOCENE FOSSIL PLANTS FROM PERU— BERRY. 285 



Class MONOCOTYLEDONAE. 



Order ARECALES. 

 Family ARECACEAE. 



IRIARTITES, new genus. 



This genus is proposed as a convenient-form genus for tlie remains 

 of fossil palms that appear to belong to the tribe Iriartcac, but whose 

 exact generic identity is uncertain. 



Type of the genus. — Iriarfites tu7nbeBensis, new species. 



IRIARTITES TUMBFZENSIS. new epecSes. 



Plate 14. 



Description. — Feather palms with leaves of large size, the exact 

 dimensions unknown. The fossil material shows much crowded 

 linear-lanceolate rays attached to the upper surface of a stout promi- 

 nently keeled rachis. The rays are slightly, if at all, narrowed at the 

 base, and have a maximum width in the preserved material of 1.5 cm. 

 Their estimated length is about 30 cm., although it may have been 

 more than this, since no lengths of single rays have been preserved 

 for a greater distance than 15 cm. In the latter, however, no diminu- 

 tion of width is shown in that distance. The rays have entire 

 margins and a keeled and fairly stout midrib. There are about 25 

 fine, largely immersed, parallel laterals on either side of the mid- 

 rib, three or four of which, equally spaced, arc somewhat thicker 

 than the intervening ones. The texture of the leaf is coriaceous. 



No remains of fossil palm leaves exactly like these have hereto- 

 fore been described. They are exceedingly abundant in the present 

 collection, the clays being packed with broken fragments of rays, 

 and the number of pieces of clay as large as one's hand that are 

 covered with regularly arranged rays indicates that the greater part 

 of leaves several feet in length were preserved and broken up in 

 collecting them. The largest complete fragment that remains is 

 shown on plate 14, two-thirds natural size. 



Among existing palms the fossil is most naturally to be compared 

 with the various members of the tribes Geonomiae, Iriarteae, 

 Morenieac, and Bactrideae, and of these I regard the Iriarteae and 

 Morenieae, especially the former, as offering the most likely compari- 

 sons. As elaborated by Drude, the Iriarteae comprise five genera 

 and 25 or more species, vvdiose center of maximum development is 

 the upper Amazon region and the Andean valleys in Colombia and 

 Ecuador. Species of Iriartea extend northward to Costa Rica and 

 southward east of the Andes to Bolivia and throughout the Orinoco 

 and Amazon basins. The other existing genera of this tribe, except 



