228 
PERNS : BRITISH AND FOREIGN. 
116. HEMIDICTYUM, Presl. 
Vernation fasciculate, erect. Fronds pinnate, 10-14 feet long ; 
pinnae 1-2 feet long, 3-5 inches wide. Veins forked ; venules 
parallel till near the margin, then anastomosing and reticulated, 
Genua 116. — Portion of fertile pinna, under side. No. 1. 
combined by a transverse, continuous, marginal vein. Sporangia 
produced on the superior side of the parallel veins, constituting 
unilateral, linear sori. Indusium plane. 
1. H. marginatum, Presl ; Hook. Gen. Fil. t. 55 A. Asple- 
nium marginatum, Linn. {Plum. Fil. t. 106) ; Hook. 
Fil. Exot. t. 73 ; Lowe’s Ferns, 5, t. 53. Diplazium 
giganteum, Hort. Linden . — Tropical America. 
117. CETERACH, Willd. ; J. Sm. 
Vernation fasciculate, erect, caespitose. Fronds 2-12 inches 
long, sinuose-pinnatifid or pinnate, the under side densely squa- 
mose. Veins forked, anastomosing. Sporangia unilateral, 
protruding through the dense squamae, forming oblong sori. 
Indusium obsolete. 
