PECOPTERIDEAE 469 



Pecopteris, and there are two other species in which 

 this was probably the case. As Mr. Kidston says : 

 " Having shown that the supposed sporangia of one 

 species of the genus {Crossotheca] are in reality the 

 microsporangia of one of the Pteridosperms, I think we 

 are justified in provisionally concluding that all the 

 remaining species also belong to the Pteridospermeae, 

 even though we do not possess a complete knowledge 

 of the structure of their microsporangia." There is 

 thus a presumption that a considerable fraction of the 

 old genus Pecopteris is made up of seed-bearing plants. 



One of the probable Pecopteroid Crossothecas, 

 Pecopteris exigua, Ren., 1 from the Permo-Carboniferous of 

 Autun, occurs in the silicified condition, with structure 

 preserved, but only fertile portions of the frond appear 

 to be known. The little fertile pinnules, elliptical in 

 form and about 1 mm. long, are inserted on the rachis 

 like the leaflets of a Pecopteris. Each pinnule bears, 

 on its lower surface, two rows of ovoid, pointed 

 sporangia, three or four in each row ; they appear to 

 be free from each other, and do not show the bilocular 

 structure described by Mr. Kidston in the Crossotheca of 

 Lyginodendron. There is, of course, no proof that they 

 were microsporangia, but the general resemblance to a 

 Crossotheca tells in favour of this supposition. 



In Callipteris , a characteristic Permian genus of com- 

 paratively small bipinnate fronds, placed by M. Zeiller 

 in Pecopterideae, M. Grand'Eury has found evidence 

 that seeds were present in at least two species. The 

 seeds, which appear to have been borne on a slender, 



1 Renault, Cours de Bot. Fossile, annee 3, p. 115, Plate xix. Figs. 

 13-18, 1883. 



