164 CHAEACTERS OF 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.— Plattloma, /. Sm. (1841). 

 Pellaa, sp. Hook. Sj}. Fil. 



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 

 Iiroad compound, continuous, marginal sorus, sub-included 

 under the revolute indusceform margin of the segments, 

 which in some is very narrow. 



Type. Adiantum paradoxum, B. Br. 



lUust. 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. 



Orw — Hitherto the species of this genus stood under 

 the tribe Pterideo', 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 1 must remark that several species of the genus Pellira 

 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 Forth America. 



