174 CHARACTERS OF TRIBES AND GENERA. 



Veins uniform, reticulated, forming transverse elongated, 

 hexagonoid areoles. Receptacles compital, elongated on the 

 exterior, transverse anastomose, forming a linear, con- 

 tinuous, marginal sorus. 



Type. Pteris angustifolia, Swartz. 



Illust. Hook, and Bauer, t. 77 A. ; J. Sin., Ferns, Brit. 

 and For., fig. 58. 



OBS. In general habit this genus agrees with Vittaria 

 and Antrophyum, being distinguished from the first by its 

 reticulated venation, and from Antrophyum by its strictly 

 transverse marginal sorus. As now restricted, the genus 

 consists of one species only ; a native of the West Indies, 

 and many parts of Tropical America. 



Sp. P. angustifolia, Desv. (v v.) (Tcenitis, Hook. Sp. Fil). 



82. DICTYOXIPHIUM, Hook. (1838). 



Vernation fasciculate, erect, acaulose. Fronds simple, 

 linear-lanceolate, attenuated and decurrent on the stipes, 

 1 to 3 feet long. Veins compound anastomosing, trans- 

 versely combined at the margin by the sporangiferous 

 receptacle, which is seated in an unequal-sided extrorse 

 groove, the upper side being indusaBform and inflexed. 



Type. Dictyoxiphiuin panamense, Hook. 



Illust. Hook, and Bauer, Gen. Fil., t. 62.; J. Sin., 

 Ferns, Brit, and For., fig. 59 ; Hook., Syn. Fil., t. 2, 

 fig. 30, b. c. ; Moore, Ind. Fil., p. 23 B. 



OBS. This genus is founded on a very distinct and 

 peculiar Fern, a native of the district of New Granada, and 

 the Isthmus of Panama on the coast of the Pacific. 



It is with some hesitation that I place this genus in 

 alliance with Vittaria, from which it differs in having fas- 

 ciculate erect vernation, and in the veins being compound 



