FOSSIL PLANTS OF JANCOCATA 211 



There are a considerable number of existing species of the 

 South American region that are very similar to this fossil 

 form, as for example, Pteris polyphylla (Presl) and Pteris 

 deftexa Link of the Brazilian area, or Pteris coriacea Desv. 

 of Peru. The last two have what Ettingshausen called the 

 "Alethopteris" venation, namely with furcate laterals. The 

 first has what this author called the "dictyopteris composita" 

 venation, and is hence most like the fossil form. In some 

 respects the latter is intermediate in character, the simplifi- 

 cation of the venation being due to the narrowing of the 

 lobes and the great depth of the intervening sinuses. The 

 fossil is somewhat smaller than the existing Pteris polyphylla, 

 with deeper sinuses, but is otherwise very similar to it. 



I do not know the upper limits of range of the most similar 

 modern members of the genus, but the genus occur in 

 equatorial South America up to altitudes of 10,000 feet where 

 the humidity is sufficient, and possibly still higher. 



The present species, which is obviously new, is named in 

 allusion to the Bolivian province in which it was found. 



Phylum Angiospermophyta 



Class MONOCOTYLEDONS 



Order POALEo 



Family POACE^E 



Genus PHRAGMITES Trinius 



Phragmites sp. 



Striated stem fragments and broken leaves are not un- 

 common in the tuffs at Jancocata. They are obviously too 

 incomplete to warrant specific diagnosis, but are of interest 

 as indicative of the presence of a large reed-like grass in this 

 flora. They appear to be most similar to the existing Phrag- 

 mites vulgaris, whose upper limit in Peru, according to Web- 

 erbauer, is 3,000 meters. Other Poaceae or Cyperacese that 

 reach comparable altitudes in the existing flora of Bolivia 

 are the Totora, Scirpus riparius Presl, of Lake Titicaca and 



