10 ARKIV FÖR BOTANIK. BAND 17. N:0 1. 



can be judged in their flattened state, are larger than those of 

 Angiopteris. It may be that the sporangial wall is thicker in 

 Danaeopsis and thus the actual capacity of the sporangium 

 smaller. 



From the above description of the Scanian specimens of 

 Danaeopsis fecunda and a comparative study of D. marantacea, 

 it is evident that the usual comparison of Danaeopsis with 

 the recent genus Danaea is entirely unwarranted. The spor- 

 angia are not fused to form synangia and do not open by 

 pores. [Stur, in the diagnose published by Krasser (see 

 above, p. 5), alone among all authors who have dealt with 

 this subject, gives the right interpretation of the soral struc- 

 ture.] The sporangia are separate and open by longitudinal 

 slits a^ in Angiopteris and Archangiopteris. The resemblance 

 to Archangiopteris is considerably the greater one, this genus 

 having more elongated sori than Angiopteris. In Danaeopsis 

 the sori are still longer than in Archangiopteris, running the 

 whole length from the midrib to the margin. If these forms 

 are really on the same line of descent, their respective geolog- 

 ical age would seem to be rather more consistent with a short- 

 ening of the sorus than with its elongation during the course 

 of descent. 



Riiffordia (Dunk.) Sew. 



The characteristic Wealden plant Sphenopteris Göpperti 

 Dunk, has been shown by Prof. Seward (1894, p. 76) to have 

 a characteristic type of fertile pinnae very different from the 

 sterile ones. On account of this character Seward refers the 

 species to a separate genus. Ruf for dia. 



Fertile fronds of Buffordia resemble those of some species 

 of the recent genus Aneimia, and Seward therefore doubt- 

 fully referred Buffordia to the Schizaeaceae (Seward 1. c. 

 and 1910, p. 350). Later on, Seward (1913, p. 91, text-fig. 

 2 A. ) discovered the spores of Buffordia Göpperti in a specimen 

 from the Wealden of Hastings. The spores were found to be 

 characterized by the presence of numerous ridges. This 

 structure recalls a characteristic feature of the spores of many 

 members of recent Schizaeaceae and thus supports the idea 

 that Buffordia is a member of that family. 



