294 CHAEACTEES Or TRIBES ASD GENERA. 



allies, but are distinguished by tlie lower pair of venules of 

 each fascicle anastomosing-, forming a row of elongated 

 transverse areoles on each side of the mid-rib, which 

 character I originally considered to be only a simple state 

 ot Litohrochia ; I, however, now deem it best to adopt it 

 as a transition genus between Pteris and LitohrocliM. 



Sp. C. nemoralis {WiUd.) (v v.) ; C. biaurita, {Linn.) 

 (v V.) ; C. geminata {Agarclh.) 



Natives of the tropics of the Eastern and Western 

 hemispheres. No less than thirty-eight synonyms are 

 placed under C. biaurita by Dr. C. Luerssen. 



168.— HiSTiOPTEEis, Affardh. (1839). 

 Pteris sp. auct., Hoolc. Sj). Fil. 



Vernation uniserial, distant ; sarmentum elongated, 

 generally epigeous and hirsute squamose. Fronds 1 to b 

 feet high, or sometimes scandent, and then ascending to 

 1!\ or 18 feet, bi-tripinnate, smooth or glaucous beneath; 

 primary pinnse and pinnules generally horizontally patent, 

 always opposite and sessile, the lower pair of pinnules of 

 each pinna? often short and stipuliform, ultimate pinnules or 

 seg-ments entire, sinuose or pinnatifid. Vei)is anastomosed, 

 or sometimes free. Eecejjtades transverse, continuous 

 across the anastomoses of the venules, forming a linear, 

 marginal sorus, furnished with an exterior attached, linear 

 indusium. 



Type. Pteris vespertilionis, Labill. 



Illust. Mett. Fil. Hort. Bot. Lips., p. 59, t. 14. 



Oes. — This genus consists of a few species of peculiar 

 habit, differing from Litobrociiia in the same manner that 

 Orniiliopteris does from Pteris, in this case, as in others, 

 habit being- the most obvious distinction. 



