V. PTERIDE.E. 



Stipes not articulate to the rhizome; frond at least pinnate, in most 

 species more or less deltoid; sori near the margin, on the ends of the 

 veins, or a strand connecting their ends, protected, except in Nothochlaena, 

 by the inflexed and modified margin of the frond. 



1. Sorus on inner face of reflexed lobe (35) Adiantum 



1. Sori on main body of frond, on tips of veins. 

 2. Fronds not dimorphous. 



3. Indusium continuous (36) Doryopteris 



3. Indusium interrupted. 



4. Sori distinct and solitary (37) Hypolejns 



4. Sori more or less confluent (38) Cheilanthes 



3. Indusium wanting (39) Nothochlaena 



2. Fronds dimorphous (40) Plagiogyria 



1. Sori on intramarginal strand connecting vein tips. 

 2. Extrorse indusium wanting. 



3. Ultimate divisions fine, almost covered by sori (41) Onychium 



3. Ultimate divisions more ample. 



4. Lowest pinnules like others (42) Pteris 



4. Lowest pinnules stipule-like (43) Histiopte7-is 



2. Extrorse indusium typically present. 



3. Stipe with many vascular strands (44) Pteridium 



3. Stipe with one vascular strand (45) Paesia 



(Ceratopteris, a fern growing in brackish or fresh marshes, may be looked for 

 here ; it is not in the Polypodiaceai.) 



(35) ADIANTUM Linnaeus. 



Stipes not articulate to rhizome, usually black and polished; frond, 

 in our species, pinnate to tripinnate, pinnse inclined to be dimidiate; por- 

 tions of the margin of the pinnules altered and reflexed, and a sorus borne 

 on the inside of each such portion and protected by it. A natural genus 

 of chiefly terrestrial ferns of most graceful habit, universally cultivated 

 under the name of "maiden-hair." 



1. Sporangia springing only from veinlets. 



2. Frond simply pinnate, apex rooting. 



3. Frond glabrous, pinnules stalked. 



4. Rachis not winged (1) A. philippense 



4. Rachis winged (2) A. alatiim 



3. Frond hairy (3) A. caudatum 



2. Frond tripinnate (4) A. Capillus-Veneris 



1. Sporangia on veinlets and parenchyma between them. 



2. Stipe and rachis glabrous (5) A. diaphanum 



2. Stipe and rachis squamulose (6) A. hispidulum 



92 



