CHARACTERS OF TRIBES AND GENERA. ES 
previously characterised under the name of Athyrium, - 
which has been viewed by most authors as a section of 
Asplenium, but which, for the sake of natural arrangement, 
I have adopted as a genus, and restricting true Allantodia 
to the present species, 
Sp. A. Brunoniana, Wall. 
Hab. A native of Ceylon, Nepal, and Java, also found in 
Otaheite. 
193.—H EurptorYUM, Presl (1836). 
Asplenium, sect. Hemidictyum, Hook. Sp. Fil. 
Vernation fasciculate, erect, arboroid. Fronds pinnate, — 
12 to 14 feet long; pinns sessile cordate, from 1 to 14 
feet long, by 3 to 4 inches wide. Veins forked; venules 
. parallel till near the margin, then anastomosing and reti- — — 
. culated, combined by a transverse continuous marginal 
. vein. Sporangia produced on the anterior side of the 
parallel venules, constituting unilateral linear sori. Zwe- 
-~ dusium plain. 
Type. Asplenium marginatum, Linn. 
Illust. Hook. and Bauer Gen. Fil, t. 55 A.; Moore bd 
Fil, p. 38 A.; J. Sm. Ferns, Brit. and For., fig. 116; 
- Hook. Syn. Fil., t. 4, fig. 38 h. 
: Ors .—This genus is founded on a magnificent Heer, a 
native of Tropical America and West India Islands, having _ 
.&stem 5 to 6 feet in height, bearing a crown of pinnate 
. fronds, measuring 12 to 14 feet in length. The chief point 
that distinguishes it from <Allantodia is in the indusium 
being plane and in the exterior margin of the reticulated 
 venation being combined by a transverse vein running 
parallel with and close to the margin. These slight dif- 
: ferences a are "rcd sufficient to characterise it as a genus 
