no. 1760. FOSSIL PLANTS OF THE POTOMAC GROUP -BERRY. C)27 



absence of better data has followed (he same course, although the 

 definite reference of the two species of Baieropsis above mentioned 

 to the Schizieacea? throws doubt upon all the other similar form-. 

 Potonie a places the genus as a synonym of his Palmatopteris in the 

 artificial group of Sphenopterides. 



Acrostichojtfrris may be compared with the modern Actinopteris, a 

 monotypic genus of the Indoafrican steppes, with the neotropical 

 genus Rhipidopteris, or with Schizsea dichotoma Swart/., and Schizsea 

 elegans Swartz, of the family Schizseacese. It is not closely related 

 to Acrostichophyllum Yelenovsky (1889) of the Cenomanien of Bohe- 

 mia. As here delimited it is purely a form genus embracing five 

 species in the Maryland-Virginia region. Of these, two species are 

 confined to the basal beds or Patuxent formation, two species range 

 through the whole Lower Cretaceous of this region and are present 

 as well in both the Lakota and Fuson formations of the Black Hills 

 region, and one species is confined to the Patapsco formation and is 

 widespread in its occurrence. One additional species, suggestive of 

 Acrost'ultopteris parvifolia of the Patuxent and likewise close to the 

 only remaining species, Acrostichopteris ruffordi Seward b of the 

 English Wealden, has recently been described by Knowlton r from 

 the Kootenai of Montana. Considering for a moment the Portuguese 

 honiot axial deposits we find a considerable number of remarkably 

 similar forms described by Saporta d , all of which are referred to the 

 form-genus Sphenopteris. Thus from the Upper Jurassic there is 

 Sphenopteris tenellisecta Saporta, from the Urgonien S. cuneifida 

 Saporta, from the Aptien S . flabdlisecta Saporta, S. U nuifissa Saporta, 

 and S. debilior Saporta. These forms are certainly congeneric with 

 Acrostichopft ris and with more representative material doubtless 

 some species would be found to be common to both sides of the At- 

 lantic. Some are more nearly like the forms segregated by Fontaine 

 to form his genus Baieropsis, while others are of the type which this 

 author referred to Acrostichopteris. 



ACROSTICHOPTERIS LONGIPENNIS Fontaine emend, 



Acrostichopteris longipennis Fontaine, Monogr. U. S. Geol. Surv., No. (5, L890, 



p. 107, pi. 170, fi^. 10; pi. 171, figs. 1, 5, 7. — Fontaine, in Ward, Monogr. 



U.S. Geol. Surv., No. 48, 1905, p. 557. 

 Acrostichopteris densifolia Fontaine, Monogr. U. S. Geol. Surv., No. 15, L890 



(part), pi. 170, fig. 11; pi. 171, figs. 2, (i; pi. L7J, fig. L3 (nol pi. 94, fig. 1, 



which is referable t<> .1. parvifolia Fontaine). 

 Acrostichopteris parvifolia Fontaine, in Ward, Monogr. U. S. Geol. Surv., No. 



is. L905, ]». 558, pi. L16, fig. •">. 



aPotoni.'' in Engler and Prantl, L902, p. 490. 



''Seward, Wealden Flora, pt. 1, L894, p. 61, pi. 6, fig. :i. 



'• Knowlton, Smiths. Misc. Coll., vol. 50, L907, p. 1 10, pi. !», figs. :*, 3«. 



d Saporta, flora Fobs. Portugal, 1894, pp. 25, (I!), L27, L60, L61. 



