1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 89 



DESCRIPTION OF TWO SPECIES OF PALMOXYLON-ONE NEW— 



FROM LOUISIANA. 



BY F. H. KNOWLTON, ASS'T CURATOR FOSSIL PLANTS. 



(With Plate xxx.) 



On February 29, 1880, several specimen's of fossil palms were received 

 in the Department of Fossil Plants of the U. S. National Museum that 

 had been collected by Mr. Lewis C. Johnson, of the U. S. Geological Sur- 

 vey, in Eapides Parish, Ln. They appeared to be very well preserved 

 fragments, in some cases nearly 8 inches in diameter, and from 3 to a 

 inches in length. They are completely silicified, aud are yellowish-gray 

 in color. The fibro-vascular bundles show very distinctly in transverse 

 section, and their irregular or undulating course through the stone is also 

 clearly shown when broken longitudinally. 



The difficulties in the way of the satisfactory determination of mono 

 cotyledons, by a study of iuterual structure alone, are much greater 

 than the determination from similar parts of conifers or dicotyledons. 

 The reasons for this are, that monocotyledonous stems are in general 

 less susceptible of satisfactory preservation in the fossil state, consist- 

 ing as they do largely of parenchematous tissue, with large intercellu- 

 lar spaces ; and also because the study of living forms, which furnishes 

 the basis for all studies of fossil forms, has not been as exhaustively 

 undertaken. Particularly is this true of the study of fossil palms. So 

 little is at present known regarding the internal structure of the living- 

 species that it is only possible in the present state of our knowledge to 

 mass together all the fossil species under the comprehensive generic 

 name of Palmoxylon, or simply " palm- wood." It is true that the de- 

 scribed species of Palmoxylon differ considerably among themselves, 

 and it is more than probable that characters will ultimately be obtained 

 that will allow of a separation into several generic types. 



Two generic types, Fasciculites and Palmacites, were recognized by 

 the earlier writers, mainly from the microscopic appearance of the 

 trunks; but Schenk, who had opportunity of studying much of the 

 original material as preserved in the Dresden Museum, concluded that 

 it was on the whole best to recognize only a single generic type, for which 

 he proposed the name Palmoxylon.* The most complete enumeration of 

 species is that given by Dr. Felix in his exhaustive paper on the Fossil 

 Woods of the West Indies.t Most of the species mentioned come from 

 the island of Antigua, but several are from European localities. 

 "Eagler's Botan. Jakrb., Vol. in, 1882, p. 355. 



tDie loss. Holz. Westhulieus. Samuil. palaout, Abhaudl., Ser. i, Heft 1. Cassel, 

 1883, pp. 22-27, PI. iv, v. 



