POLYPODIACE^. 



Chiefly perennial plants, rarely annual, and rarely arborescent; 

 leaves (called fronds) with the tissues of flowering plants — 

 epidermal, fibro-vascular, and fundamental ; spores borne in stalked 

 sporangia with incomplete longitudinal annulus and transverse 

 stomium. 



Families of the Polypodiacecv. 



Stipe not articulate to the rhizome ; sorus dorsal on its vein ; 

 indusiuna fastened beneath the sorus on all sides, ruptur- 

 ing irregularly over it (p. 14) I. Woodsie.b 



Fronds not articulate to the rhizone ; sort dorsal or terminal 

 on their veins, usually round, exceptionally extending 

 along the veins or over the parenchyma ; indusia fixed 

 by the center or at the top of a basal sinus, frequently 

 wanting (p. 15) II- Aspidie.^ 



Stipe articulate to the rhizome, or not ; sori, except in 

 Oleandra, terminal on the veins, often on the margin of 

 the frond, and the margin modified in connection with 

 them ; indusium opening toward the margin or obliquely, 

 wanting in Moiiaclwsorum (p. 45) Ill- Davallie.b 



Stipe, except in StenochlcEna, not articulate to the rizhome ; 

 sori superficial, springing from the sides of the fertile 

 veins ; indusium opening on the side away from the vein 

 or irregularly in Allantodia) or wanting (p. 66) IV. Asplenie.B 



stipe not articulate to the rhizome ; sori near the margin, 

 on the ends of the veins or a strand connecting their 

 ends, protected, except in Nothochlcena, by the inflexed 

 and modified margin of the frond (p. 92) V. Pteridk.e 



Fronds simple and entire, not articulate to the rhizome ; 



sori marginal or dorsal, linear, usually immersed (p. lOG).. VI. Vittarie.b 



stipes articulate to the rhizome ; sori terminal or dorsal on 

 the veins usually of definite form and size, without 

 indusia (p. 110) VII. Polypodie.* 



Fronds articulate to the rhizome or not ; sporangia cover- 

 ing the fertile surface, without being collected Into sori ; 

 indusia therefore wanting (p. 136) VIII. Achrosticheje 



Artificial key to the families and erratic genera. 



1. Sori indefinite, covering the dorsal surface, in- 

 dusium wanting {Achroslicltum L.). 

 2. Fertile region restricted to specialized apex 



of simple frond (49) Hymenolcpis 



11 



