CHARACTERS OF TRIBES AND GENERA. 129 



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. Acrostichum citrifolium, Linn. 



Illust. Moore Ind. Fil., p. 44, B. ; J. Sm. Ferns, Brit, and 

 For., fig. 32 ; Hook. syn. Fil., t. 6, fig. 59, B. 



OBS. In my definition of the genera of Ferns, 1841, 

 I noticed the peculiarities of this Fern, and in 184G 

 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 Fee in Antrophyum, but the sporangia being thinly 

 scattered over the whole under-disk indicate its relationship 

 to be with Acrostichese. 



Sp. A. citrifolium (Linn.) (v v.). (Hemionitis parisitica, 

 Linn.). 



A native of the West Indies, growing on trees. 



Sect. 2. POLYBOTRYEJ;. 



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. RHIPIDOPTERIS, Schott. (1834). 



Acrostichum sp., Hook. Sp. Fil. 



Vernation uniserial, sarmentum slender. Fronds flabel- 

 liform, stipate, 3 to 6 inches long, the sterile dichotomously 



