Vl. POLYPODIACEAE. § 2. ASPIWEAE. 125 



h. Veins free. 



c. Leaflets very unequal-sided, the upper base broadly cuneate 



or subtruncate, the lower obliquely cut away. 



f. Indusium oblong, terminal on the veins; leaflets articulate 



to the rachis. No. 20. Didyniochlaena. 



f.f. Indusium round, rarely reniform; leaflets not articulate 



to the rachis. No. 19. Polysticbum. 



C.C. Leaflets + equal-sided and if unequal-sided/the lower base not 



or slightly cut away. 



d. Fronds pinnate; pinnae articulate to the rachis; main veins 

 simple or forked. Indusium round or reniform. 

 e. Indusium round, peltate, without a sinus. 



No. 18. Cyclopeltis. 



e.e. Indusium reniform, sinus present, the lobes sometimes 



meeting or overlapping and then the indusium becoming 



round and subpeltate. No. 17. Mephrolcpiis. 



d-d. Fronds generally variously divided; leaflets not articulate; 



main veins pinnate. Indusium reniform, rarely round. 



No. 22. Uryopteris, S Lastraea. 

 b.b. Veins more or less anastomosing. 



1. Lowest veins of contiguous groups forming a costal row of 

 regular, + deltoid areolae on each side, the tops of which with 

 an excurrent veinlet, which is either free or joining in the 

 angles of the superior pairs of veins, which often form 1 

 or more rows of regular, + rhomboidal areolae between the 

 costal ones and the margin. 

 f . Indusium reniform, rarely round. 



No. 22. Dryopteris, § Nephrodium. 

 f.f. Indusium oblong, + 3 X as long as broad. 



No. 25. Meiiochlaena. 

 1.1. Veins not anastomosing as in 1. 



3. Lower veins forming 1 — 2 rows of irregular costal areolae, 

 the rest free or slightly anastomosing near the main veins. 

 Indusium reniform. No. 21. Pleocnemia. 



S.3. Veins anastomosing copiously and mostly irregularly. 



3. Sori alternate, in 3 — 4 rows on each side of the 

 midrib. Indusium oblong, + 3 X as long as broad. 

 Fronds simple. No. 24. liuerssenia. 



