222 Systematic Paleontology 



form the species Schiz(Bopsis americana, and which differ but slightly 

 in frond characters from the members of the present genus. Further- 

 more, there is the close resemblance between the sterile fronds of tliis 

 genus and those of Ruffordia, which, upon fairly satisfactory grounds, 

 has been referred by Seward {loc. cit.) to the Schizseacese. 



Acrostichopteris may be compared with the modern Actinopteris, a 

 monotypic genus of the Indoafrican steppes, with the neotropical genus 

 Rhipidopteris, or with ScMzcea dichotoma Sw. and ScJiizcea elegans Sw. 

 of the family Schizseacese. It is not closely related to Acrostichopliyllum 

 Velenovsky (1889), of the Cenomanian of Bohemia. As here delimited 

 it embraces six species in the Maryland- Virginia region. Of these, three 

 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 re- 

 gion, and one species is confined to the Patapsco formation and is wide- 

 spread in its occurrence. One additional species, suggestive of- Acrosti- 

 chopteris parvifolia of the Patuxent formation, and likewise close to 

 the only remaining species, Acrostichopteris Ruff or di Seward^ of the 

 English Wealden, has recently been described by Knowlton^ from the 

 Kootanie of Montana. Considering for a moment the Portuguese homo- 

 taxial deposits we find a considerable number of remarkably similar 

 forms described by Saporta,^ all of which are referred to the form-genus 

 Sphenopteris. Thus from the "Upper Jurassic there is Sphenopteris 

 tenellisecta Sap., from the Urgonian 8. cuneifida Sap., from the Aptian 

 S. flabellisecta Sap., S. tenuifissa Sap., and S. dehilior Sap. These 

 forms are certainly congeneric with Acrostichopteris, and with more 

 representative material doubtless some species would be found to be 

 common to both sides of the Atlantic. 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. 



^ Seward, Wealden Fl., pt. i, 1894, p. 61, pi. vi, fig. 3. 



^ Knowlton, Smith. Misc. Coll., vol. 1, 1907, p. 110, pi. xi, figs. 3, 3a. 



' Saporta, Fl. Foss. Portugal, 1894, pp. 25, 69, 127, 160, 161. 



