294 Systematic PAiiEOXTOLOGY 



Angiopteridium pachyphyllum Fontaine, 1890, Mon. U. S. Geol. Surv., vol. 



XV, 1889, p. 115, pi. xxix, fig. 5. 

 Angiopteridium strictinerve Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 



1889, p. 116, pi. xxix, figs. 8, 9 (non Font., in Ward, 1906). 

 Angiopteridium strictinerve latifolium Fontaine, 1890, Mon. U. S. Geol. 



Surv., vol. XV, 1889, p. 116, pi. xxx, figs. 1, 5. 

 Anomozamites angustifoUus Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 



1889, p. 167, pi. xxx, fig. 3 (non. fig. 2). 

 Anomozamites virginicus Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 



1889, p. 168, pi. xxx, fig. 4; pi. xxxi, fig. 3. 

 Angiopteridium strictinerve latifolium Fontaine, 1906, in Ward, Mon. U. S. 



Geol. Survey, vol. xlviii, 1905, p. 241, pi. Ixvi, figs. 8-10. 

 Twniopteris nervosum Berry, 1910, Proc. U. S. Natl. Mus., vol. xxxviii, p. 



634. 



Description. — Habit unknown, indications in one or two specimens 

 that the frond was pinnate in character. Pinnge (or frond) linear-lan- 

 ceolate to elongate-lanceolate. Length unknown, apparently ranging 

 from 10 cm. to 30 cm. Maximum width 1.2 cm. to 5 cm. Texture cori- 

 aceous. Midrib rather stout and prominent. Lateral veins thin but dis- 

 tinct, especially on the lower surface, more or less closely placed, parallel, 

 curving backward from the midrib, and then straight or slightly curved 

 upward to the margin. Angle of divergence \vide, 45° to 90°. Veins 

 either simple or forked, the forking usually near the base, both kinds 

 often shown on a single specimen. 



This species is based entirely upon very fragmentary material, which 

 served Fontaine for the differentiation of five species of Angiopteridium 

 and two species of Anomozamites. There is absolutely no ground for the 

 reference of any of the material to the genus Anomozamites, and it is 

 all obviously identical. There is some slight variation from specimen to 

 specimen, for example the midrib is somewhat less stout in Angiopteri- 

 dium nervosum and densinerve, as delimited by Fontaine, and the angle 

 of divergence is somewhat more acute in the latter, but these are not char- 

 acters of specific value. If similar recent fronds, such as those of 

 Oleandra, Angiopteris, or Marattia be examined, the size of the midrib, 

 the remoteness or closeness of the lateral veins and their angle of di- 

 vergence will be found to vary through much wider limits, a single frond 

 often exhibiting the extremes in this respect. 



