2 
COPELAND. 
KEY TO THE FAMILIES OF FILICALES. 
Sporangium derived from a group of cells, wall more than 1 cell thick (Euspor- 
ANGIATAE ) . 
Sporangia solitary, marginal on reduced segments 1. Ophioglossaceae 
Sporangia in sori, dorsal, on normal fronds 2. Marattiaccae 
Sporangium derived from a single cell; wall 1 cell thick (Leptosporangiatae) . 
Spores of two kinds; aquatic plants ( Hydropteridineae ) . 
Leaves cruciform 3. Marsileaceae 
Leaves not cruciform, plants floating 4. Salviniaceae 
Spores of one kind, mostly terrestrial (Eufilicineae) . 
Leaves with the usual leaf tissues. 
Sporangium opening by a longitudinal slit. 
Annulus rudimentary 5. Osmundaceae 
Annulus subapical G. Schizaeaceae 
Annulus medial 7. Gleicheniaceae 
Sporangium opening by a more or less transverse slit. 
Annulus oblique. 
Aquatic 8. Parkcriaceae 
Not aquatic, rhizome creeping 9. Matoniaceae 
Not aquatic, caudex erect, mostly tree ferns 10. Gycitheaceae 
Annulus longitudinal, incomplete 12. Polypodiaceae 
Leaves without stomata, usually without parenchyma.. 11. Hymenophyllaceae 
artificial key. 
Aquatic, leaves cruciform Marsilea, p. 12 
Aquatic, leaves simple, floating plants. 
Midrib present, but no veinlets Azolla, p. 14 
Veinlets present Salvinia, p. 14 
Aquatic, leaves pinnately compound Ceratopteris, p. 2G 
Terrestrial, stipules present Marattiace^e, p. 8 
Terrestrial, stipules wanting. 
Frond forked into a sterile segment and a fertile one arising from it or below it. 
Ophioglossaceae, p. 3 
Frond not forked into a sterile and a fertile segment. 
Leaves mostly very thin, sori terminal, inclosed by two equal thin valves 
( Hymenophyllace.e ) . 
Leaves mostly thicker, sori not inclosed by two equal thin valves. 
Rachis scandent, monopodial (dichotomous) Ly podium, p. 17 
Frond grass- or rush-like, digitate or dichotomous at top Schizaea, p. 20 
Fronds monopodial, pendent Phanerosorus, p. 28 
Fronds not monopodial, nor grass-like with digitate or dichotomous apex. 
Frond fan-shaped, with pinnate divisions Matonia, p. 27 
Frond not fan-shapped with pinnate divisions. 
Ultimate divisions pinnate, frond equally dichotomous below these. 
Gleichenia , p. 22 
Frond not dichotomous and then pinnate. 
Sporangia large, opening by a slit across the apex Osmunda, p. 15 
Sporangia not opening by a slit across the apex. 
Tree-ferns with oblique annulus Cyatiieace.e, p. 28 
Not tree-ferns with oblique annulus. 
Annulus oblique, frond at least tripinnate Balantium, p. 61 
Annuls not oblique, or frond but once pinnate' ( Polypodiace.-e ) . 
