IMPROVEMENT IN THE ARRANGEMENT OP FERNS. 365 



3. Polypodiaeese : Sporangia with the ring vertical and complete' 



* Sori naked. 



-j- Sori indefinite on certain parts of the frond. 



Tribes : 



1. Taenitidinse. 



Sori intra-marginal, linear, extending to 

 the interstices. 



2. Haemionitidinse. 



Sori on the veins. 



3. Acrostichinge. 



Sori over the surface or some portion of it. 



■}" "j" Sori definite. 



Tribes : 



1. Vittariinse. 



Sori in a marginal groove. 



2. Grammitidings. 



Sori elongated, scattered. 



3. Polypodiinje. 



Sori round, scattered. 



* * Sori indusiate. 



° Indusium underneath the sorus. 

 Hypindusiatse. 



Tribes : 



1. Davalliinse. 



Sori marginal, indusium eup-shaped or bi- 

 valvate. 



2. Dicksoniinse. 



Sori submarginal or scattared, termioating 

 a vein j indusium lateral bivalvate. 



3. Peraneminse. 



• Sori round, scattered; indusium lobed or 



fringed. 

 °° Indusium covering the sorus with lateral or central 

 attachment. 



Epindusiatae. 



