194 CHAEACTEES 0¥ TRIBES AXD GENERA, 



98. Amphiblestea, Presl. (1836). 

 Pteris, S2\, E. and P., Rool:, Sp. Fil. 



Vernation fasciculate, erect (?). Fronds stipate, 2 to 3 

 feet liig-h, pinnate, membraneous, flaccid, pinna? 2 to 3 pairs, 

 oblong acuminate, petiolate, 8 inches or more in length, 

 2 to 3 inctes broad, entire or the lower ones lobed, sub- 

 pinnatifid. Primarij veins costajform, venules compound 

 anastomosing, -with free vcinlets terminating in tbe areoles. 

 Beceptacles compital, contiguous, forming- a linear sub- 

 continuous marginal sorus, included under or near to the 

 narrow inflexed membraneous industeform margin. 



Type. Pla-is latifolia, II. and P. 



Illust. Hook, and Bauer, Gen. Fil., t. 120, C ; Moore, 

 Ind. Fil., t. 33, A. Both copied from Presl. 



Obs. — This genus is founded on a remarkable and rare 

 Fern, first described by Willdenow in 1810, from specimens 

 collected in Venezuela by Humboldt and Bonpland. At 

 the time of the jiublication of Hooker and Bauer's " Genera 

 Filicum " I had not seen specimens of this Fern, and there- 

 fore followed Presl in retaining it in Ptcridcw ; having 

 subsequently received specimens, 1 find its natural asso- 

 ciation to be with Drijonienes, Dictijopteris, and Aspidium, 

 especially such as A. macroplvjllum, with which it agrees 

 in habit and venation, but diflers from Aspidiuin in having 

 the sporangia produced close to the margin, and forming 

 an apparent linear sorus parallel with the margin which is 

 inflexed in the form of a narrow membraneous indusinm, 

 which circumstance led authors to refer it to Ptcris. I, how- 

 ever, view this Fern as an aberrant form of the Aspidcw 

 alliance. 



Sp. A. latifolia, Pr,, Kze. Schk., Snpp, II, , 13, t. 118. 



