99. piLioBs. 431 



covered by an indusiuiE opening longitudinally on one side, 

 placed on the side of tlie lateral veins. 



,,7-; Athyridm. Clusters oblong-reniform. Ind,usiuni open- 

 ing towards the central vein or midrib, margin fringed. 



8. AsPLBNitTM. Clusters long, straight. Jndusium, opening 

 towards the central vein or midrib, nearly flat. 



9. ScoLOPENDBiuM. Clustei;? Ipng, sti;aight,, 2 together. 

 Indusia of each pair opening towards each other. 



10. Ceteeach. Lateral veins anastomosing ; clusters attached 

 to their middle on the side next the; midrib, except in the 

 lowest. Indusium (?) a narrow nearly erect membrane on 

 the back of the vein. Whole, back of the frond covpre(^, 

 with chafiy scales. 



[11. Gymnogbamme. : Clusters oblong or linear on both 

 branches of the forked vein, becoming confluent and cover- 

 ing the back of the frond. Indusium wanting.] 



Tr. IV. ABIANTE^. Capsules covered by a marginal or 

 submargiijal elongated, part of the frond, or Ijy a separated 

 portionOf the cuticle resembling aii iiidusiuiti. ''■' 



12. Blechnum. Capsules in a continuous line parallel to 

 the midrib upon a longitudinal , anastomosing part of the 

 transverse veins, covered by a continuous soanous indu- 

 sium. — Barren arid fertile fronds dissimilar in our plant, 



13. Ptbeis.' Capsules'in a cblitinuous marginal Hne covered 

 by a coiitinuous indusium formed of the reflexed margin. 



14. Adiantdm. Capsule?, marginal, oblong or roundish,; 

 covered by distinct reflexed portions of the margin of the 

 frond. 



tt Capsule opening irregularly, seated on a receptacle which ends 

 a^ve'in' at the edge- of the frond. Sing oblique, transverse, 



Tr. V. HYMENOPHTLLEJE. 



16. Tbiohomanes. Capsules on a, long filiform receptacle 

 within a cupshaped involucre of ^he saine texture, with the. 

 fcpnd. 



16. Hymenophyllum. Capsules on a narrow subclavate 

 receptacle within a, twb-valved involucre of the Same texture' ' 

 with the frond. ' -, 



