22 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



mountains sufficiently high to harbor that mixture of temperate types 

 such as is seen at the present time in the mountains of Central 

 America, as, for example, above 6,000 feet in Costa Rica. There was 

 plenty of opportunity for the introduction of such types had the 

 climate been propitious, so that I would infer that the Tertiary relief 

 was slight, that is under 5,000 feet and probably much less than this, 

 although there is no evidence to warrant precision of statement. 



On the other hand, the collected floras do not furnish an}' traces 

 of the characteristic vegetations of low muddy shores, although types 

 like Rhizophora, Avicennia, Conocarpus, Laguncularia, etc., were 

 already in existence in Eocene times as we know from their presence 

 in the Mississippi embayment of that time, where they were undoubt- 

 edly derived from the south. I do not infer that these costal types 

 were absent in the Tertiary flora of the Isthmus. On the contrary 

 they must have been present; but no traces of them have been dis- 

 covered except the traces of Acrostichum in the Culebra formation. 



The bulk of the fossil plants clearly belong to the evergreen rain 

 forests and they have the appearance of having been washed into 

 the basins of sedimentation by streams. None of the lithologic speci- 

 mens that I have seen from the Isthmus indicate autochonous swamp 

 deposits either of coastal or valley situations and I picture the flora 

 as one of a humid tropical character covering a country of low hills. 

 This is of necessity a tentative conclusion and perhaps even such 

 general deductions are unwarranted because of the very limited data 

 with which I have had to deal. 



FLORA OF THE CANAL ZONE. 



Arecales : 



Arecaceae — 



Palmoxylon palmacites (Sprengel) Stenzel. 

 Urticales : 



Moraceae — 



Ficus culebrensis, new species. 

 Ranales : 



Anonaceae — 



Guatteria culebrensis, new species. 

 Myristicaceae — 



Myristicophyllum panamense, new species. 

 Rosales : 



Leguminosae — 



Taenioxylon multiradiatum Felix. 

 Inga oligocaenica, new species. 

 Cassia culebrensis, new species. 



