452 100. FiLicBs. 



Tr. II. ASPIBIJEjS. Clusters nearly circular, covered by an 

 indusium, seated upon the back of the lateral veins. 



4. Lasteba. Indusium reniform, attached by the notch. 

 Veins distinct after leaving the midrib, not uniting with 

 those of the adjoining lobe. 



5. PoLTSTicHTTM. ludusium circular, attached by the centre. 

 Veins distinct after leaving the midrib. 



6. Cystoptebis. Indusium attached by its broad hooded 

 case under the clusters, with a long fringed free extremity 

 at first covering the capsules. 



Tr. in. ASPLENIEJE. Clusters oblong or linear, usually 

 covered by an indusium opening longitudinally on one side, 

 placed on the side of the lateral veins. 



7. Athyeittm. Clusters oblong-reniform. Indusium open- 

 ing towards the central vein or midrib, margin fringed. 



8. AsPLENiUM. Clusters long, straight. Indusium opening 

 towards the central vein or midrib, nearly flat. 



9. Scolophndrittm:. Clusters long, straight, 2 together. 

 Indusia of each pair opening towards each othe r 



10. Cbtebach. Lateral veins anastomosing; clusters attached 

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

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

 the back of the vein. Whole back of the frond covered 

 with chaffy scales. 



[11. Gymnogbammb. 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. ADIANTE^. Capsules covered by a marginal or 

 submarginal elongated part of the frond, or by a separated 

 portion of the cuticle resembling an indusium. 



12. Blbchnum. Capslues ia a continuous line parallel to 

 the midrib upon a longitudinal anastomosing part of the 

 transverse veins, covered by a continuous scarious indu- 

 sium. — Barren and fertile fronds dissimilar in our plant. 



13. Ptbbis. Capsules in a continuous marginal line covered 

 by a continuous indusium formed of the reflexed margin. 



14. Adiantttm. Capsules marginal, oblong or roundish, 



