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(a) Rhizome wide-creeping. Only one 
pair of veins anastomosing, rarely two in 
unitum. 
(t) Venation and sori anomalous. 
1. N. subpectinatum. 
(2) A swamp fern; no auricles on 
the pinne. 
2. N. umtum. 
(iit) Sori confined to the lobes. 
3. N. pterordes. 
(1v) Venation often as in Lasérea, 
when anastomosing the angle 
acute at the apex. 
4. N. extensum. 
(6) Rhizome erect, sub-erect, or occa- 
sionally somewhat creeping in molle and 
pennigerum Two or more pair of veins 
anastomosing occasionally, only one in molle. 
(1) Herbaceous, more or less hairy, 
auricles present or absent, 1-2 
pair of veins anastomose. 
5. N. molle. 
