FILICES. 3 
Sori linear, placed on a vein. Indusium doubie; one opening 
towards the midrib, the other away from it 17. DipLtazium. 
Sori linear, attached to a vein. Indusium single, opening towards 
the midrib - 18. ASPLENIUM. 
Sori long, linear, attached y; transverse pomniaee running parallel 
to the midrib. Indusium opening towards the midrib .. 19. BLrecHNum. 
Sori short, oblong, on transverse veins joining the main veins. 
Indusium opening towards the midrib 1 « .. 20. Doopta. 
**** Sori marginal. Indusium composed of the more or less modified margin of 
the frond, which is reflexed over the sori, thus opening inwards. 
Sori cblong or linear, simple or sage often confluent. 
Indusium wanting . 21. GYMNOGRAMME. 
Sori confluent into a linear band along the margin of the pinnae. 
Indusium continuous .. 22, PELLAEA. 
Sori oblong, ultimately confluent, often contested by the tefiexed 
but barely altered margin of the frond .... . 23. NoOTHOCHLAENA. 
Sori subglobose or oblong, often confluent into linear masses. 
Indusium composed of the modified and reflexed margin of the 
frond 24, CHEILANTHES. 
Sori globose, distinct, in the notches of the. “ltunabe: ai visions 
of the frond. Indusium a modified and reflexed portion of the 
margin of the frond i ' 25. HYPOLEPIS. 
Sori reniform or globose or oblong. Indusium an altered and 
reflexed lobe or tooth of the frond, bearing the sorus on its 
under-surface .. 7: f we re .. 26. ADIANTUM. 
Sori marginal, linear, continuous. Indusium always single. 
Veins free or anastomosing. Spores tetrahedral .. . 27, PTERIS. 
Sori marginal, linear, continuous. Indusium always single. 
Veins free or anastomosing. Habit of Pteridiwm. Spores 
bilateral : cs es bei .. 28, HISTIOPTERIS 
Sori marginal, linear, continuous. Indusium double, outer the 
reflexed margin of the frond, inner arising from the receptacle. 
Spores tetrahedral “3 29. PrERIDIUM. 
Sori marginal, lnear, continuous.  Indusium usually double. 
Fronds more finely cut than in Pteridium. Spores bilateral... 30. Pawsta. 
#%**** Sori dorsal, remote from the margin of the frond. Indusium wanting. Fronds 
articulated on the rhizome (Eremobryoid). 
Fronds simple or compound, glabrous ; or indumentum, if present, 
composed of simple hairs or scales . .. 31. PoLYPoDIum. 
Fronds simple, sometimes dimorphous, under-surface covered 
with matted stellate hairs a sf A. .. 32, CYCLOPHORUS, 
Suborder IV. GLEIcHENIACEAE. Sori dorsal, naked, of few (2-6) sporangia ; receptacle 
not elevated. Sporangia sessile or nearly so, splitting vertically, surrounded by a 
complete transverse ring. 
Fronds dichotomously forked; ultimate branches pinnately 
divided ef ti “i: “J a .. 33. GLEICHENIA. 
Suborder V. ScutzmaceAE. Sporangia crowded, not collected into distinct sori, sessile 
or nearly so, with a complete transverse ring just below the apex, splitting vertically. 
Fertile portions of the frond much modified. 
Fronds simple or forked or flabellately divided, without an 
expanded lamina. Sporangia in 2-4 rows on the under-surface 
of short linear fertile pinnae terminating the fronds. . ..» 34. SCHIZAA. 
Fronds very long, climbing; primary pinnae dichotomously or 
pinnately divided. Sporangia i in 2 rows on the under-surface of 
contracted fertile pinnules a sth sh .. 35. LyGoprium. 
Suborder VI. OSMUNDACEAE. Sori irregular, distinct or confluent, dorsal; indusium 
wanting. Sporangia sessile or nearly so, splitting vertically ; ring rudimentary, placed 
just below the apex. 
Fronds coriaceous, dense and opaque io yl .. 36. TODRA 
Fronds membranous, thin and translucen’ .. a .. ot, LEPTOPTERIS 
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