I 'O I .Y P O n lU M .
P H L E B O D IU M . R. B r o w n .
T h e v e i n s a r e p in n a t e o r b r a n c h e d , t h e v e n u l e s a r c u a t c l y o r
a n g u l a r l y a n a s t o m o s in g , f o rm i n g o n t h e i r a n g u l a r m e e t in g s o r
e x t e r i o r s id e tw o v e in le t s , w h i c h a r e s p o r a n g i f e r o u s w h e r e t h e
two veinlets join.
Sori round or oval, transversely uniserial, or multiseriah
Differing from GoniopMehium by having the lower venules
combined,"the sori being formed at the apex or point of junction.
D R Y N A R IA . B o r y .
T h e v e in s a r e m o s t l y c o s tæ f o rm , p a r a l l e l , o r f le x u o s e ; v e n u l e s
c o m p o u n d a n a s t o m o s in g .
The sporangia is produced on the angles or points of confluence
of numerous veinlets.
Sori circular or oblong; transversely uniserlal, or in one or
two oblique rows between each pair of primary veins, or irre g ular.
Sori forming protuberances on the u p p e r or superior
side of the frond.
T h e frond smooth and thick.
Differing from Phlebodium by the venation being more compound,
and by the sori being situated where a number of
venules join.
The B ritish representatives of this genus are Polypodium vulgare,
P .pheg o p te ris, P . alpestre, P . dryopteris, and P . calcareum.
Pe rhaps the N o rth American P . hexagonopterum of Michaux
may eventually be added to this list.