98 CHAEACTERS OF TRIBES AND GENEEA. 



further reduced. Presl, however, not only maintains the 

 highest number of specie but goes the length of creating 

 no less than six additional genera. It is true that their 

 venation and position of the sori is variable, but in all 

 cases it is simple modifications of compound anastomosing, 

 which is principally due to the more or less contracted 

 state of the fronds, and which has led Presl to place the 

 same species under different genera. The only very 

 evident distinction is in habit, which admits of their being 

 arranged under two sections, one having an elongated 

 caudex, and the other with contiguous ceespitose fronds. 



• Gaudex elongated surculate. Fronds distant, the fertile 

 specially contracted ; primary veins undefined. 



Sp. IST. nummularifolius {Sw.) ; N. rupestris (E. Br.) (v v.) 

 N. serpens (Forst.) ; N. acrostichoides {Forst.) ; N. albicans 

 {Bl.) ; N. Lingua (Tlmml.) (v v.) ; N. tricuspe {Thumb.) 

 (vv.) 



Obs. — The numerous and intermediate forms and sizes 

 of the preceding species from different localities render it 

 almost impossible to collate and separate them into distinct 

 species when many specimens are brought under view. 

 The different form and colour of the scales of the caudex 

 indicate specific characters, but even that seems to alter 

 according to age. 



** Caudex sliort, ccespitose. Fertile and sterile fronds 

 nearly uniform. Primary veins defined. 



IS. Gardneri {Meiten.) (v v.) ; N. africana {Kunze) ; N. 

 porosus {Wall) ; N. flocoulosus {Bon) ; Bedd. F. Brit. Ind. 

 pi. 162 sul. ; N. costatus {Wall.) (v v.) ; N. splendens {Pr.) ; 

 N. Penangiana {Hooh) ; N. subfurfuracea {Hook.) ; N. 

 Boothii {Hooh.). 



