164 CHARACTEES OP TRIBES AND GENERA. 



OBS. The last named is a native of Mexico, Cuba, and 

 other parts of Tropical America, the other five are natives 

 of India, Malayan Peninsula and islands, and Japan. 



74. PLATYLOMA, /. 8m. (1841). 



Pellcea, sp. Hook. Sp. Fit. 



Vernation uniserial, erect or decumbent, acaulose. Fronds 

 pinnate or bipinnate, smooth, 1, 2, or more feet high ; 

 segments articulate with the rachis. Veins forked, their 

 venules free, their upper portion sporangiferous, forming 

 oblong sori, which become laterally confluent, forming a 

 broad compound, continuous, marginal sorus, sub-included 

 under the revolute indusa3form margin of the segments, 

 which in some is very narrow. 



Type. Adiantum paradoxum, R. Br. 



Illust. Hook, and Bauer, Gen. Fil., t. 115, A ; Hook. 

 Fil. Exot., t. 21 and 48 ; Moore Ind. Fil., p. 52 B ; 

 J. Sm. Ferns, Brit, and For., fig. 92. 



OBS. Hitherto the species of this genus stood under 

 the tribe Pteridece, but the sporangia being borne on free 

 veins, and as they agree in habit and general aspect with 

 Llavea, I therefore deem this section their natural place ; 

 but I must remark that several species of the genus Pellcea 

 have a strong claim of relationship with Platyloma, and 

 are only distinguished from the latter by the sporangia 

 being- borne on the combined apices of the veins, forming a 

 continuous sorus on the axis of the indusium, as in true 

 Pteris. 



This genus consists of about a dozen species, widely 

 distributed, being represented in Australia, New Zealand, 

 South Africa, as also tropical and temperate North America. 



