ADDENDUM. 



By a regrettable oversight no mention has been made in the text 

 of the interesting new genus Loxsomopsis, described by Dr. Christ as 

 having been discovered in Costa Rica (Bull, dc I'Herb. Boissier, 2me 

 ser., tome iv., p. 393, 1904). This rare Fern, still unknown as 

 regards stipe and rhizome, shows a habit like that of Loxsoma, but larger. 

 The outline of the leaf, especially at the base of the pinnae, shows 

 archaic characters, while the sori correspond in general features to those 

 of Loxsoma ; but the sporangia have a lateral dehiscence, and a complete 

 ring composed of very numerous cells. In these details Loxsomopsis 

 corresponds to Thyrsopteris. Pending a better knowledge of its characters 

 and especially of its anatomy, it may be accorded a place in the 

 neighbourhood of Loxsoma and Thyrsopteris, about the base of the 

 series of Gradatae (compare p. 655, and Fig. 354). 



