122 VI. POLYPODIACEAE. 



or more commonly miiting the apices of several veins. Indusium 

 marginal, i. e. consisting of the recurved or reflexed, modified edge 

 of the frond or portions of the edge, opening inwardly. Stipes not 

 articulate to the rhizome. 



§5. BLECHNEAE. Sori oblong or linear, distentfrom the margin, parallel 

 to the central ribs of the free or joined ultimate segments. Indusium 

 of the same shape, not marginal, attached at the outer side of the 

 sorus, opening inwardly. Stipes not articulate to the rhizome. 



§6. ASPLENIEAE. Sori oblong or linear, straight or more or less re- 

 curved, rarely horseshoe-shaped, springing from the sides of the veins 

 like the indusia, mostly oblique to the costa, rarely placed between 

 the veins or occupying the single central vein of narrow, ultimate 

 segments. Indusium of the same shape, opening towards the costa 

 or sometimes towards the margin, if double opening towards opposite 

 directions. Stipes rarely articulate to the rhizome. 

 B. Exindnsiatae. Indusium wanting. 



§ 7. PHEGOPTERiDEAE. Sori punctiform, round or oblong, rarely more 

 than 2 X as long as broad, medial or terminal on the veins, if 

 medial the opposite pairs somentimes confluent, if terminal someti- 

 mes running into a submarginal line or more or less covered hy^ 

 recurved, not modified margin of the frond. Stipes not articulate 

 to the rhizome 



§8. GYMNOGRAMMEAE. Sori linear or linear-oblong, more than 2 X 

 as long as broad, several on each side of the costa, mostly oblique 

 to tho la t tM^ ^or running longitudinally and irregularly along the veins, 

 free, joining or ± reticulate. Stipes not articulate to the rhizome. 



§ 9. GRAMMITIDEAE. Sori linear, one on each side of the costa, parallel 

 to the latter or the margin, continuous or interrupted. Stipes not 

 articulate to the rhizome. 



§10. POLYPODIEAE. Sori punctiform, round, oblong or linear and then 

 either oblique or parallel to the costa or the margin. Stipes articulate 

 to the rhizome. 



§ 11. ACROSTICHEAE. Sori indefinite, the sporangia densely crowded 

 over the under surface of the fronds or portions of the under surface 

 or occasionally extending + on both sides of the fronds or segments, 

 not rarely becoming narrowly linear when the fertile/segments are 

 much Gontraeted. Stipes whether or not articulate to the rhizome. 



