928 FILICES. [Hymenophyllum. 
Indusium reniform and attached by the sinus. Fronds 
usually 2-4-pinnate; pinnae not articulated to the 
rhachis... .. 20, NEPHRODIUM. 
Indusium reniform and attached by the sinus. Fronds 
pinnate ; pinne articulated to the rhachis’ .. .. 21. NEPHROLEPIS. 
** Indusium altogether absent. 
Sori globose or broadly oblong, dorsal, distinct .. . 22. PoLyPpopium. 
Sori oblong or rounded, at first distinct but ultimately 
confluent, marginal, often partly concealed by the re- 
flexed margin of the frond and then barely distinguish- 
able from Cheilanthes aie ss vi .. 23. NOTHOCHLENA. 
Sori oblong or linear, see or forked, often confluent, 
dorsal ae ; 4c so 5. .. 24, GYMNOGRAMME. 
Suborder IV. GLBICHENIACEA. Sort dorsal, naked, of few (2-6) sporangia ; 
receptacle not elevated. Sporangia sessile or nearly so, splitting vertically, 
surrounded by a complete transverse ring. 
Fronds nari gies forked; ultimate branches epinpatey, 
divided .. ; c 56 .. 25, GLEICHENIA. 
Suborder V. ScuHizmaceEm. 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 mone terminating the 
fronds aie . 26. ScHIzzma. 
Fronds very long, climbing ; ‘primary pine dichotom- 
ously or pinnately divided. Sporangia in 2 rows on the 
under-surface of contracted fertile pinnules .. .. 27. LyGopium. 
Suborder VI. OsmMuNDACEa. Sori irregular, distinct or confluent, dorsal ; in- 
dusium wanting. Sporangia sessile or nearly so, splitting vertically ; ring 
rudimentary, placed just below the apex. 
Fronds opaque or translucent, 2—3-pinnate fs .. 28. Topma. 
Suborder VIT, Maratrtacna. Sori distinct, dorsal. Sporangia sessile, with- 
out any ring, coriaceous, splitting vertically or opening oy a pore at the 
apex, usually cohering im concrete masses called synangia. 
Rhizome large, tuberous. Fronds large, 2-3-pinnate .. 29. MARatTta. 
Suborder VIII. OPpHioGLossacea. Sporangia globose, coriaceous, sessile, with- 
out any ring, dehiscing by a transverse or vertical slit, crowded on a linear 
spike or on the branches of a panicle. Fronds not circinate im vernation. 
Sterile frond simple and entire. Sporangia on a linear 
spike 36 wif ms .. 30. OPHIOGLOSSUM. 
Sterile frond pinnate or 2-4-pinnate. Sporangia on the 
linear branches of a panicle.. Ae bs .. 31. BotrycHIuM. 
1. HYMENOPHYLLUM, Linn. 
Usually small and sometimes minute ferns. Rhizome slender, 
creeping, often much branched and matted. Fronds simple or more 
generally compound, delicately membranous, often pellucid, usually 
of a single layer of cells; segments entire or toothed at the margin, 
