CHARACTERS OF TRIBES AND GENERA. 179 



87.— XiPHOPTERis, Kaulf. (1824). 

 Graminitis sp. Siv. ; Polypodkun spi-, Hook. Sp. Fit. 



Vernation sarmentose, slender, sub-ascending. Fronds 

 contiguous, sub-fasciculate, 2 to 6 inches high, linear, 

 dentate-serrate, or pinnatifid below, sub-entire, and plicate 

 or nearly plane above. Vk'his simple, free, very short. 

 Sporangia borne on the short venules, forming oblong sori 

 conniving with the mid-rib, included in the plicate apex of 

 the frond. 



Type. Grammitis serrulata, Swartz. 



Illust. Hook., Gard. Ferns, t. 44; Hook., Exot. Fil., 

 t. 78; Moore, Ind. ML, p. 14 B. ; J. Sm., Ferjis 

 Brit, and For., fig. 48. 



Obs, ^Distinguished from Pleurograiiiina by the sori 

 being oblong and diverging from the mid-rib, but becoming'- 

 confluent. 



Sp. X. serrulata, Kaulf. (v v.) ; X. myosuroides, Kaiilj. 

 X. Jamesoni, Hook. Second Cent. Ferns, t. 14. 



Obs. — In the " Species Filicum " the above three species 

 are considered as forms of one only. As regards X. Janif- 

 soni (of which I have not seen specimens), it is said that 

 the texture is so rigid that the thread-like mid-rib remains 

 after the pinna; fall. This singularity appears to me to bo 

 sufficient to mark it as a distinct species. They have a wide 

 geographical range through Tropical America, the West 

 Indies, Sandwich Islands, and also West Tropical Africa ; 

 X. serrulata being one of the few Ferns common to both 

 Continents. 



88.— Grammitis, Sw., in part (1800). 

 Pohjpodium s^}., auct., and Hook Sp. Fil. 

 Vernation fasciculate, erect, acaulose or sarmentose. 

 Fronds linear-lanceolate, entire, rarely sub-pinnatifid, plane, 



