ON GENERA AND SPECIES. 69 



instance, in C. arborea and G. serra, the fronds are terminal, 

 forming the characteristic corona common to tree Ferns. 

 When mature they separate from the stem, leaving- a clean 

 scar similar to Eremobrya, thus differing from the adherent 

 vernation characteristic of the mass of the species of the 

 tribe Cyathea ; but as they agree in all the essential 

 characters as regards the nature of their fronds and fructi- 

 fication, it is therefore necessary to obtain more evidence 

 as to the mode of evolution and structure of these tree 

 Ferns before any satisfactory conclusion can be arrived at, 

 as to enable us to view it as a special character to mark 

 distinct genera.* 



This now leads me to notice another family of Ferns 

 namely, Marattiacece, which have a very distinct and 

 special habit from other Ferns, and are well marked by the 

 sporangia being destitute of a ring. The evolution of the 

 frond is terminal and articulate to the caudex, as in Cyathea 

 arborea above noticed, but differs in the fronds rising 

 from between two stipuliform appendages in the form of 

 a socket, analogous to the stipules of phsenog'amous plants. 

 The speciality of this group of Ferns leads me to view it 

 as constituting a distinct division, which I have named 

 Scaphobrya. 



This division comprehends but a small number of species 

 as compared with Eremobrya and Desmobrya, the number 

 probably not exceeding thirty or forty, the principal part 

 of which are included under the genera Marattia, Angi- 

 opteris and Danea. 



* Since the above was written, a valuable memoir " On the Structure 

 and Formation of the Stems of the Tree Ferns of India," has been 

 published in the thirtieth volume of the Transactions of the Linneau 

 Society, 1874, by Mr. J. Scott, Curator of the Botanic Gardens, 

 Calcutta. It consists of thirty-nine pages of letterpress, accompanied 

 by eighteen plates. 



