CHARACTERS OF TRIBES AND GENERA. 295 



Although the species are to all appearances few, their 

 wide distribution has led to the creation of above a dozen 

 species, which in the " Species Filicum " are reduced to five, 

 and in the " Synopsis " to one only. Their mode and places 

 of growth are similar to 0. aquilina ; among bushes or 

 underwood they assume a scandent character, and often 

 attain a great length. They are chiefly found within or 

 near the tropics of both the old and new world, their most 

 southern limit being Tasmania. 



. Sp. H. incisa ( Thunb.) (v v.) ; H. vespertilionis (Lab.) 

 (v v.) (New. Roll, t. 245) ; H. aurita (El.) (v v.) (Mett. Fil. 

 Hort. Lips, t. 14) ; H. sinuata (Brack. Fil., t. 14). 



Sect. 2. Veins free. 



169. PTERIS, Linn, in part (1737). 

 Hook. Sp. Fil. 



Vernation fasciculate and erect or decumbent, or sarmen- 

 tose uniserial. Fronds pinnate, bi-tri-quadripinnate, rarely 

 simple, from a few inches to 6 or 7 feet high ; the ultimate 

 segments entire, sinuose, lobed or pinnatifid. Veins forked ; 

 sterile venules free, the apices of the fertile transversely 

 combined by the receptacle, forming a linear marginal 

 sorus, furnished with an exterior attached linear indusium. 



Type. Pteris longifolia, Linn. 



Illust. Hook, and Bauer, Gen. Fil., t. 64 A. ; Moore, Tnd. 

 Fil., p. 30, fig. 14 ; J. Sm., Ferns, Brit, and For., 

 fig. 96 ; Hook., Syn. Fil., t. 3, fig. 31 a. b. 



OBS. This is an extensive genus, containing according 

 to the "Species Filicum" about sixty-three species, but 

 which, in the " Synopsis" are reduced to forty- two. The 

 species present great variation in the circumscription of 



