GENEEA OF FERNS AND THEIR CLASSIFICATION. 71 
Division I. — Eremolrya. 
Fronds articulated with the rhizome. 
Tribe I. Oleandrecc. — Sori round, medial, intra -marginal. 
sium lateral, interiorly attached, or sometimes central 
plane. 
II. Davallese. — Sori round, terminal, marginal. Indusium 
lateral, interiorly attached, vertically urceolate. 
III. Polypodece. — Sori round or linear, naked. 
Division II. — Desmoirya. 
Fronds adherent to the stem. 
Tribe IV. Acrosticheae. — Sori amorphous, naked. 
V. Grammiteae. — Sori oblong or linear, simple, forked, or 
reticulated, naked. 
VI. Phegopterideoe. — Sori round, rarely linear, naked or 
indusiate. Indusium lateral, interiorly attached or 
central, or rarely calyciform. 
VII. Pteride*. — Sori marginal, round, or linear and trans- 
verse. Indusium lateral, exteriorly attached on the 
margin. 
VIII. Blechnese. — Sori intra-marginal, linear, transverse. 
Indusium lateral, exteriorly attached. 
IX. Asplenese. — Sori linear, oblique. Indusium lateral. 
X. Dicksonese. — Sori marginal, round, or linear and 
transverse. Indusium lateral, interiorly attached, 
conniving with the changed margin, forming a groove 
O O 0 7 O O 
or urceolate sub-bivalved cyst. 
XI. Cyatheae. — Sori round, intra-marginal. Receptacles 
elevated. — Indusium calyciform, or lateral and inte- 
riorly attached or absent. 
Sub-Order II. — Glcichcniacece. 
Ring horizontal. ( Sori intra-marginal.) 
Sub-Order III. — Uymenophyllacea:. 
Ring horizontal or oblique, ( Sori marginal.) 
