﻿VI. POLYPODIACEAE. § 4. PTERIDEAE. 129 



C.C. Fronds mostly divided; leaflets not articulate to 

 the rachis. 

 d. Veins free. 



e. Spores bilateral, ± bean-shaped ; indusium 

 mostly double. No. 46. Paesia. 



e.e. Spores globose to tetrahedral; indusium 

 always single. 



f. Fronds finely dissected. Sori and 

 indusia + meeting against the 

 midribs of the very small and narrow^ 

 ultimate segments. 



No. 44. Onychium. 

 f.f. Fronds not finely dissected. Sori and 

 indusia not meeting. Ultimate seg- 

 ments not very small. 



No. 45. Pterin. 

 d.d. Veins anastomosing more or less copiously. 

 >!>:. Stipes black. 



No. 42. DoryopteriiS, § Eudoryopteris. 

 ^.i(.. Stipes not black. No. 4S. Pteriis. 

 a.a. Stipes with 3 or more, free vascular strands. 



.'. Stipes with 2 stout and 1 to several finer strands 



placed altogether in a circle. Fronds dimorphous, at 



utmost 2-pinnatifid. No. 48. l^omaria. 



.'..'. Stipes with many (12 — 24) irregularly placed strands. 



Fronds uniform, at least 2-pinnate at the base. 



No. 47. Pierichiuiu. 



§ 5. BLECHNEAE. 



Sori superficial. 



2. Sori long, linear, 1 on each side of and + close to the midribs 

 of the ultimate segments, continuous or interrupted. 

 3. Fronds dimorphous; fertile pinnae much contracted and the 

 sori filling up nearly the whole space between the margin 

 and the costa. Indusium submarginal. (No. 48. JLotnaria). 

 3.3. Fronds not dimorphous; fertile pinnae not contracted; sori 

 distant from the margin like the indusia. 

 FmcES. 9 



