﻿GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 25 



narrowly compressed and elongated parallel to the sides of the 

 bundles. Their diameter varies from 0.035 mm. to 0.10 mm. Scat- 

 tered through the stem parenchyma are darker cells which in polar- 

 ized light appear to be gum cells. They are slightly larger than the 

 parenchyma cells, being from 0.072 mm. to 0.108 mm. in diameter. 



Occasional bundles are seen to be branching. These are the fas- 

 ciculi fbbroduGto7'es or Kreuzungsbiindel. 



This species was first recognized by Sprengel in 1828, who referred 

 it to Endogenites; Cotta four years later transferred it to Fasciculites, 

 and Corda in 1845 referred it to Palmacites. When Felix came to 

 publish on the Antigua woods in 1883 he recognized this species, 

 but in describing it under the genus Pal/nioxylon which had been 

 proposed by Schenk only a year or two before he took the liberty 

 of giving it the new name of tenerum, which under the rules of 

 nomenclature has no standing as Stenzel recognized in print in 1904, 



The specimen from Panama is small and may be from near the 

 periphery of a stem, although in the group Lunuria there is little 

 difference between the central and peripheral regions. In the size, 

 outline, and crowding of the fibrovascular bundles as well as in the 

 character of the parenchj'^ma of the groundmass the present species 

 greatly resembles Palmoxylon integi'um, described by Felix ^ from 

 Cuba and considered by Stenzel ^ as merely a variety of the Antiguan 

 species Pahnoxylon antiguense (Unger) Felix.^ It differs from that 

 species in altogether lacking the numerous auxiliary sclerenchyma 

 bundles which are so well marked in Pahnoxylon integrum. A fur- 

 ther difference is the presence of gum or mucilage cells which are 

 fairl}'- numerous in the Panama specimen of Palmoxylon palmacites 

 and which might upon a merely superficial examination be mistaken 

 for auxiliary sclerenchyma bundles. Among the Oligocene species 

 of Palmoxylon from the southern United States Pahnoxylon missis- 

 sippefise Stenzel * is very similar to the present species. 



Other described fossil species which show more or less resem- 

 blances are Palmoxylon stellatum, ascJiersoni, varidbile., and ceylani- 

 cum. The nearest affinity among recent palms is not determinable 

 in the present state of our knowledge of the anatomy of the latter. 

 The present type of structure is commonly known as the Cocos- 

 like type. 



For some unknown reason the upper Eocene and lower Oligocene 

 in southeastern North America abounds in silicified palm wood. 

 Palm leaves are often very abundant in the Wilcox and Claiborne 

 Eocene and in the Apalachicola Oligocene; but all of the petrified 



■ Felix, Foss. Holz. Westindlens, p. 24, pi. 5, flg. 2, 1S83. 

 » Stenzel, Foss. Palmenholzer, p. 154, pi. 1, flgs. 1-10, 1904. 

 » Felix. Foss. Holz. Westlndiens, p. 22, pi. 4, flg. 5. 

 * Stenzel, Foss. Palmenholzer, p. 248, pi. 21, flgs. 254-265. 



