MATONIBItm. 73 



respects both with the Gleicheniaeese and CyatheacsEe ; Micro- 

 diotyon, Guthiera, and Carolopteris may be added to this list as 

 closely alKed genera. In his memoir on the Jurassic plants from 

 the neighbourhood of Cracow, Eaciborski^ includes the two fossil 

 genera Zdccopteris and Microdidyon in the family Matonineae ; the 

 latter genus, instituted by Saporta in 1873,^ I have been led to 

 consider identical with Presl's Laccopteris. 



Genus MATONIDIUM, Schenk. 

 [PalsBontograpMca, vol. xix. p. 219, 1871.] 



This genus, founded on specimens of sterile and fertile fronds 

 from the Wealden of North Germany, is thus defined by Schenk : — 



"Folia sterilia et fertilia conformia flabellato-pinnata, segmenta 

 pinnatifida. Nervi primarii excurrentes, secundarii angulo subrecto 

 egredientes dichotomi, ramuli simplices. Son biseriales oblongi 

 indusiati. Sporangia receptaculo in ramulo affixa. Annulus 

 obliquus." 



It has been the custom to adopt Schenk's genus for such fossil 

 fronds as agree in habit and in the form of the sori with the recent 

 species Matonia peetinata, but it is advisable not to attach too 

 great prominence to the habit of the fronds as a guide to family 

 or generic affinity. The habit of Matonia sarmentosa is entirely 

 distinct from that of the other species of the genus, and it is 

 probable that older species may have existed which possessed 

 sori and sporangia of the Matonia type, but differed from Matonia 

 peetinata in the form of their leaves. Since the publication of 

 the British Museum Catalogue of Wealden ferns, in which 

 is dealt with, an interesting Cretaceous species, 

 Wiesneri, has been described by Krasser from Ceno- 

 manian rocks in Moravia, a type which exhibits a striking 

 resemblance to Matonia peetinata ; the Moravian plant approaches 

 the recent species even more closely than the allied Wealden and 

 Jurassic fern, Matonidium Ooepperti. Potonie' has suggested the 



' Eaciborski (94), p. 42. 



2 Saporta (73), p. 313. 



3 Potonie (99), p. 359. 



