406 99. FILICES, 
Order XCIX. FILICES. 
Leafy plants with a rhizome or trunk. L. or fronds with a 
circinate vernation (Tribe VIII. excepted), simple or divided. 
Fructification springing from the veins on the under side or at 
the edge of the |. and consisting of 1-celled theez stalked and 
with an elastic ring or sessile and without a ring. 
* Thece with an elastic marginal ring. 
Suborder I. POLYPODIACE, 
Thece in clusters on the back of the frond, opening trans- 
versely ; ring vertical, usually incomplete. 
Tribe I. POLYPODIEE. Sori nearly circular, without an 
indusium, seated upon the back of the lateral veins. 
]. AtLosorus. Sori circular, at length confluent, concealed 
by the reflexed margin of the frond. 
2. Potypopium. Sori circular, naked; margin of the frond 
flat, not reflexed. 
3. Woopsta. Sori circular with an inferior involucre divided 
at the edges into numerous capillary segments. 
Tr. Il. ASPIDIEA. Sori nearly circular, covered by an in- 
dusium, seated upon the back of the lateral veins. 
4. Lasrrea. Indusium reniform, attached by the sinus. 
Veins distinct after leaving the midrib, not uniting with 
those of the adjoming lobe. 
5. PotysticHum. Indusium circular, attached by the centre. 
Veins distinct after leaving the midrib. 
6. Cysropreris. Indusium attached by its broad hooded 
base under the sori, with a lengthened fringed free extremity 
at first covermg the thecze. 
Tr. WI. ASPLENIE. Sori oblong or linear, covered by an 
indusium opening longitudinally on one side, placed on the 
side of the lateral veins. 
7. ATHyRIuM. Sori oblong-reniform. Indusium opening 
towards the central nerve or midrib, margin fringed. 
8. AspLeNiIUM. Sori elongate straight. Indusium opening 
towards the central nerve or midrib, nearly flat. 
9. ScoLopenpDRIuM. Sori elongate, straight, 2 together. In- 
dusia of each pair opening towards each other. 
