﻿128 VI. POLYPODUCEAE. 



§ 4. PTERIDEAE. 



1. Indusia bearing and covering the sori. No. 37. Adiantum. 



1.1. Indusia not bearing, only covering the sori. 



2. Sori submarginal, roundish, distant, terminal on the veins, con- 

 fined to the tops of the sinusses, 1 to each sinus. Indusium 

 roundish, small, hardly covering the sorus at full maturity. 



No. 58. Hypolepis. 



2.3. Sori submarginal, either roundish or oblong, close, soon running 



into a submarginal line or linear, uniting the apices of the veins, 



not confined to the tops of the sinusses. Indusia trarisversally oblong, 



approximate, contiguous, confluent or linear. 



3. Sori terminal on the veins, free, roundish or oblong, soon 

 confluent into a submarginal line. 



4. Base of the stipe abruptly tickened, bearing + 3 — 6 

 spongy projections on the outer side. Ring oblique, com- 

 plete, as in Cyatheae. Fertile pinnae naiTow^ly linear. 



No. 40. Plagiogyria. 

 <f.4[. Base of the stipe not abruptly thickened, without projec- 

 tions. Ring vertical, incomplete. 



5. Vein tips thickened. No. 39. Clieilanteis. 



5.5. Vein tips not or hardly thickened. 



e. Fronds divided; leaflets + stalked, not adnate 

 to the rachis, more or less distinctly articulate 

 at the base. No. 41. Pellaea, $ Platyloma. 

 6.6. Fronds simple or divided; segments adnate or 

 joined, not stalked, not articulate. 

 No. 42. Ooryopteris, § Doryopteridastrum. 

 3.3. Sori linear or linear-oblong, the receptacle uniting the tips 

 of the veins, sometimes running them transver sally. 

 u. Stipes vs^ith 1 — 2, free or joining vascular strands. 



b. Fronds compoundly divided ; lowest pinnulae (secondary 

 pinnae) short, close to the rachis, stipule-like. 



No. 45. Hisliopteris. 

 b.b. Fronds simple or divided, if divided the lowest pinnulae 

 (secondary pinnae) not stipule-like. 

 c. Fronds divided; leaflets articulate to the rachis. 



No. 41. Pellaea, § Pleridella. 



