CHARACTERS OF TRIBES AND GENERA. _ 199 
smooth, membraneous. Veins uniform reticulated, forming 
trapezoid or hexagonal areoles. Receptacles undefined, 
the sporangia being thinly scattered, or collected in small 
irregular groups, over the whole under surface of the frond, 
or evident on the veins. 
Type. Aerostichwm citrifolium, Linn. 
Ilust. Moore Ind. Fil., p. 44, B. ; J. Sm. Ferns, Brit. and 
For., fig. 32; Hook. syn. Fil., t. 6, fig. 59, B. 
Oss.—In my definition of the genera of Ferns, 1841, 
I noticed the peculiarities of this Fern, and in 1846 
I adopted it as a distinct genus under Kunze's sectional 
name, Anetium. It is decidedly what may be termed an 
aberrant species. Sir. Wm. Hooker places it in Hemionitis 
and Fée in Antrophyum, but the sporangia being thinly ` 
. to be with Acrostiches. P 
Sp. A. citrifolium (Linn.) (v v.). (Hemionitis parisitica, ES 
Linn.). 
A native of the West Indies, growing on trees. 
Sect, 2. —POLYBOTRYEE. 
Vernation generally uniserial distant or contiguous. 
Fronds pinnate or bi-tripinnate, rarely flabellate, segments 
adherent. Veins free or combined at the margin or 
variously anastomosing. 
* Veins free. 
44,—Rutrrpopreris, Schott. (1834). 
Acrostichum sp., Hook. Sp. Fil. 
Vernation uniserial, sarmentum slender. Fronds flabel. ` 
iform, stipate, 3 to 6 inches long, the sterile dichotomously | = 
scattered over the whole under-disk indicate its relationship ` 
