POLYPODIACE^E. 



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 Polypodiacece. 



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



indusium fastened beneath the sorus on all sides, ruptur- 



ing irregularly over it (p. 14) ................................................ I. WOODSIE,E 



Fronds not articulate to the rhizone ; sori 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^E 



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 Monachosorum (p. 45) .......................................... III. DAVALLIE.*; 



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^E 



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. PTERIDE^E 



Fronds simple and entire, not articulate to the rhizome ; 



sori marginal or dorsal, linear, usually immersed (p. 106).. 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. POLYPODIES 



Fronds articulate to the rhizome or not ; sporangia cover- 



ing the fertile surface, without being collected into sori ; 



indusia therefore wanting (p. 136) ........................................ VIII. ACHROSTICHES 



Artificial key to the families and erratic genera. 



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

 dusium wanting (Achrostichum L.). 

 2. Fertile region restricted to specialized apex 



of simple frond 



(49) Hymenolepis 

 11 



