520 
100. FILICES. 
10. Ceterach. 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. AVhole back of the 
frond covered with chafify seniles. 
[11. Gymnogramma. 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. ADIANTEuE. Capsules covered by a marginal or 
submarginal elongated part of the frond, or by a separated 
portion of the cuticle resembling an indusium. 
12. Blechnum. Capsules in 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. Pteris. Capsules in a continuous marginal line covered 
by a continuous indusium formed of the reflexed margin. 
14. Adiantum. Capsules 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 vein at the edge of the froiuh Ring ohligite, trans- 
verse, complete. 
Tr. V. HYMENOPIIYLLE.E. 
15. Trichomanes. Capsules on a long filiform receptacle 
within a cupshaped involucre of the same texture with 
the frond. 
16. Hymenophyllum. Capsules on a narrow subclavate 
receptacle within a two-valved involucre of the same 
texture with the frond. 
** Capstdes witliout an elastic ring. 
Suborder II. OSMUNDACEiE. 
Young frond circinate. Rachis woody. Capsules regularly 
2-valved, stalked, in clusters at the extremity of the frond. 
