1	"Stems prominently jointed; leaves whorled, forming a sheath at stem nodes (horsetails)"	"Equisetum (E. hymale)"
1	"Stems not jointed; leaves absent or if present, not whorled and forming a sheath at the nodes"	2
2	"Sporangia borne on stems, in the axils of leaves or leaf-like organs, or embedded in the expanded bases of such organs (fern allies)"	3
2	"Sporangia borne otherwise (on leaves or in nut-like sporocarps) (ferns)"	10
3	"Sporangia very large, fused in pairs (synangia) and borne on the upper surface of forked leaves"	Tmesipteris
3	"Sporangia single, large (visible to the naked eye), and borne on the upper (adaxial) basal section of leaves"	4
4	"Plant heterosporous; leaves ligulate"	5
4	"Plant homosporous; leaves without a ligule"	6
5	"Leaves very small (< 10 mm in length) and scale-like. Terrestrial plant of damp soil"	Selaginella
5	"Leaves 30-700 mm in length, rosette-forming and quill-like. Aquatic or semi-aquatic plants"	Isoetes
6	"Plant growing from a tuber, with a basal rosette of cylindrical leaves and a solitary fertile spike"	"Phylloglossum (P. drummondii)"
6	"Plant spreading, upright or pendant, with numerous scale like leaves and at least several fertile spikes or regions"	7
7	"Plant stem tufted; sporophylls similar to vegetative leaves, fertile regions not markedly discernible"	8
7	"Plant stem spreading (but sometimes with erect branches); sporophylls grouped into distinct strobili"	9
8	"Sporophylls similar to vegetative leaves; gemmae often present; plants terrestrial in alpine habitats"	"Huperzia (H. australiana)"
8	"Sporophylls only slightly dissimilar to vegetative leaves - the fertile region sometimes square in cross-section; gemmae not produced; plants epiphytic, lithophytic or terrestrial from sea-level to alpine habitats"	"Phlegmariurus (P. varius)"
9	"Strobili lateral on stems or side-branches; plants of permanently moist or poorly drained soils"	Lycopodiella
9	"Strobili terminating stems or side-branches; plants of usually well-drained soils"	Lycopodium
10	"Plant aquatic (at least for part of the year)"	11
10	"Plant terrestrial, epiphytic or lithophytic"	13
11	"Plant free-floating"	"Azolla (A. rubra)"
11	"Plant rooted in mud, often immersed"	12
12	"Leaves clover-like and floating"	"Marsilea (M. mutica)"
12	"Leaves grass-like and often immersed"	"Pilularia (P. novae-hollandiae)"
13	"Plant not possessing a typical fern frond as below; sterile and fertile fronds markedly different"	14
13	"Plant possessing typical fern frond - either simple or divided, with sporangia or sori present on its underside or margin; sterile and fertile fronds similar"	17
14	"Fertile spike and vegetative leaf having a shared leaf petiole; new fronds non-circinate"	15
14	"Fertile and vegetative leaves separate; new fronds circinate"	16
15	"Leaf compound"	Botrychium
15	"Leaf simple"	"Ophioglossum (O. lusitanicum subsp. coriaceum)"
16	"Fertile lamina a comb-like structure"	Schizaea
16	"Fertile lamina a reduced version of the sterile lamina"	Blechnum
17	"Fronds small (usually < 15 cm in length) and membranous; sporangia on margins of pinnae in cup-shaped protuberances (filmy ferns)"	18
17	"Fronds small to large, herbaceous to coriaceous; sporangia on underside of fronds or on their inrolled margins"	20
18	"Fronds grey-brown, densely clothed in stellate hairs"	"Hymenophyllum (H. applanatum)"
18	"Fronds green or yellow-green, glabrous"	19
19	"Indusium short and split into two halves with no protruding bristle"	Hymenophyllum
19	"Indusium long and tubular with a long, protruding bristle"	"Polyphlebium (P. venosum)"
20	"Fronds bipinnate, monomorphic; sporangia not grouped into sori but densely spread over pinnule undersurface"	"Todea (T. barbara)"
20	"Fronds simple to quadripinnate, monomorphic or dimorphic; sporangia grouped into sori"	21
21	"Plant capable of producing a trunk > 1 m tall; base of stipe > 10 mm thick"	22
21	"Plant with ultimate trunk height of < 1 m, or no trunk at all; base of stipe < 10 mm thick"	23
22	"Stipe bases and croziers clothed with scales; sori approximately halfway between midvein and margin"	Cyathea
22	"Stipe bases and croziers clothed with hairs; sori marginal"	"Dicksonia (D. antarctica)"
23	"Sori lacking an indusium, with up to five very large sporangia easily visible to the naked eye; annual increments of frond growth in tiers (except Gleichenia abscida)"	24
23	"Sori with or without an indusium, sporangia small and numerous, not visible to the naked eye"	25
24	"Pinnules more-or-less hemispherical, < 5 mm in diameter"	Gleichenia
24	"Pinnules linear, > 10 mm in length"	Sticherus
25	"Fertile fronds lobed like the sterile fronds but with much narrower pinnae; sori parallel to pinna midrib"	Blechnum
25	"Fertile and sterile fronds similar"	26
26	"Sori marginal or appearing so; the pinnule margin often reflexed over the sori as a false indusium"	27
26	"Sori situated well away from pinnule or frond margin"	36
27	"Sori kidney-shaped"	"Adiantum (A. aethiopicum)"
27	"Sori round, linear or continuous around pinnule margin"	28
28	"Sori round"	29
28	"Sori linear or continuous around pinnule margin"	30
29	"Stipe and rachis almost glabrous except for white, non septate hairs matted at base of stipe and scattered on the rachis; indusium cup-like, formed from reflexed leaf margin and inner membranous flap"	"Calochlaena (C. dubia)"
29	"Stipe and rachis sparsely to densely covered in septate (and non-septate) hairs; indusium not present, or sori protected by the slightly reflexed leaf margin"	Hypolepis
30	"Rhizome erect"	31
30	"Rhizome short- to long-creeping"	32
31	"Sori more or less continuous around the pinna margin, protected by the reflexed margin but with no indusium"	Pteris
31	"Sori elongated along vein, oblong, and the indusium easily visible; pinna margin not reflexed"	Asplenium
32	"Rhizome very long-creeping; fronds 60-200 cm tall"	33
32	"Rhizome short- to medium-creeping; fronds < 50 cm tall"	34
33	"Lamina dark green and coriaceous; pinna midribs with shallow lobing between the ultimate pinnae; pinnule undersurface covered with brown hairs."	"Pteridium (P. esculentum subs. esculentum)"
33	"Lamina blue-green and herbaceous; all midribs smooth; pinnule undersurface glabrous"	"Histiopteris (H. incisa)"
34	"Indusium opening outwards towards the leaf margin"	Lindsaea
34	"No indusium present (sori may be protected by inrolled leaf margin)"	35
35	"Fronds pinnate; leaf margin hardly or not reflexed"	Pellaea
35	"Fronds bi- to tripinnate; leaf margin greatly reflexed"	Cheilanthes
36	"Sorus a continuous single band either side of and parallel to the pinna midvein"	Blechnum
36	"Sorus not as above"	37
37	"Fronds undivided or pinnatifid"	38
37	"Fronds pinnate or more dissected"	39
38	"Fronds usually > 15 cm in length, shiny, variable in shape but often pinnatifid; lamina veins clearly visible to the naked eye"	"Microsorum (M. pustulatum subsp. pustulatum)"
38	"Fronds < 15 cm in length, dull, undivided or pinnatifid; lamina veins not visible to the naked eye"	Notogrammitis
39	"Sori oblong to linear or, rarely, in an undefinable mass"	40
39	"Sori more or less round"	44
40	"Lamina with a dense covering of hairs"	"Pleurosorus (P. rutifolius)"
40	"Lamina not hairy"	41
41	"Sori parallel to pinna midrib"	Blechnum
41	"Sori oblique to pinna midrib"	42
42	"Sorus not protected by an indusium"	"Anogramma (A. leptophylla)"
42	"Sorus protected by an indusium, at least until spores are shed"	43
43	"Plant terrestrial; rhizome erect; base of stipe covered in non-clathrate, papery scales"	"Diplazium (D. australe)"
43	"Plant epiphytic or lithophytic, rarely terrestrial; rhizome erect or short-creeping; base of stipe with a tuft of clathrate scales"	Asplenium
44	"Immature sori without indusia, or slightly covered by reflexed leaf margin"	45
44	"Immature sori with indusia"	47
45	"Rhizome long-creeping"	Hypolepis
45	"Rhizome erect"	46
46	"Plant terrestrial; fronds > 20 cm in length; sori round"	"Pneumatopteris (P. pennigera)"
46	"Plant epiphytic or on rock; fronds < 20 cm in length; sori oval"	"Notogrammitis (N. heterophylla)"
47	"Rhizome erect; rachis heavily clothed in scales"	"Polystichum (P. proliferum)"
47	"Rhizome erect or creeping; rachis sparsely covered in scales or not at all"	48
48	"Rhizome long-creeping; frond coriaceous; indusium round, peltate"	"Rumohra (R. adiantiformis)"
48	"Rhizome erect, creeping or very short creepeing; frond herbaceous or mebranous; indusium kidney or hood-shaped, attached along its radius or at its base and arching over the sorus"	49
49	"Rhizome erect or creeping; frond herbaceous; indusium kidney-shaped, attached along its radius"	Lastreopsis
49	"Rhizome very short-creeping; frond membranous; indusium hood-shaped, attached at its base and arching over the sorus"	"Cystopteris (C. tasmanica)"