194 CHARACTERS OF TRIBES AND GENERA. 



98. AMPHIBLESTRA, Presl. (1836). 

 Pteris, sp., H. and B., Hook., Sp. Fit. 



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

 feet high, pinnate, membraneous, flaccid, pinna3 2 to 3 pairs, 

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

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

 pinnatifid. Primary veins costa3form, venules compound 

 anastomosing, with free veinlets terminating in the areoles. 

 Receptacles compital, contiguous, forming- a linear sub- 

 continuous marginal sorus, included under or near to the 

 narrow inflexed membraneous indusa3form margin. 



Type. Pteris latifolia, H. and B. 



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 publication of Hooker and Bauer's " Genera 

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

 fore followed Presl in retaining it in Pteridece; having 

 subsequently received specimens, I find its natural asso- 

 ciation to be with Dryomenes, Dictyopteris, and Aspidium, 

 especially such as A. macropliyllum, with which it agrees 

 in habit and venation, but differs from Aspidium 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 indusium, 

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

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

 alliance. 



Sp. A. latifolia, Pr., Kze. Schk., Supp. II., 43, t. 118. 



