1 | Sori more or less regularly spaced, either in a single row between costa and margin, or in two, sometimes irregular rows between the lateral veins |
1' | Sori irregularly scattered on the lamina surface |
2 | Lamina pinnatifid |
2' | Lamina simple or irregularly lobed |
3 | Rhizome white waxy, with sclerified circumvascular sheaths and scattered sclerenchyma strands |
3' | Rhizome not white waxy, with either scattered sclerenchyma strands, or scleri-fied circumvascular sheaths |
4 | Sori superficial or slightly immersed, in one to several rows between costa and margin, scales peltate |
4' | Sori deeply sunken, visible as protrusions on upper surface, in one row, generally close to the costa, at most halfway to the margin, scales pseudopeltate |
5 | Apex of lobes rounded or acute, rhizome dorsiventrally flattened, with sclerified circumvascular sheaths, lamina herbaceous, margin entire |
5' | Apex of lobes long-acuminate, the rhizome terete, with scattered sclerenchyma strands, lamina membranaceous, margin undulate |
6 | Rhizome white waxy, sori deeply sunken, visible as protrusions on the upper surface |
6' | Rhizome not white waxy, sori superficial or slightly immersed |
7 | Scales round or elliptic, peltate, 0.8-1.2 mm long, often with eroded margins, roots sparsely set |
7' | Scales (narrowly) ovate or triangular, pseudopeltate, 1.5-6.5 mm long, margins usually intact, roots densely set |
8 | Lamina base narrowly angustate, decurrent into a long wing, rhizome with sclerified circumvascular sheaths and scattered sclerenchyma strands, sori in two (irregular) rows between each pair of veins |
8' | Lamina base truncate-angustate or cuneate-angustate, rhizome with only scattered sclerenchyma strands or not sclerified at all, one row of sori between costa and margin, generally close to the costa, at most halfway to the margin. |
9 | Rhizome without sclerenchyma strands or sclerified circumvascular sheaths. |
9' | Rhizome with circumvascular sclerified sheaths or scattered strands of sclerenchyma |
10 | Rhizome with only scattered strands of sclerenchyma, rhizome white waxy underneath the scales |
10' | Rhizome with circumvascular sheaths, rhizome not white waxy underneath the scales |
11 | Rhizome with circumvascular sclerified sheaths and scattered strands of sclerenchyma |
11' | Rhizome with only circumvascular sheaths |
12 | Sclerenchyma strands 50-100, scales densely set, slightly to distinctly spreading, phyllopodia 1.5-6 cm apart, lamina herbaceous |
12' | Sclerenchyma strands 8-15, scales apically densely set, elsewhere more sparsely set, appressed, phyllopodia to 1.1 cm apart, lamina thin-herbaceous. |
13 | Venation with one row of large areoles parallel to the costa, costal areole, if present, formed by smaller veins |
13' | Venation with several rows of more or less equally sized areoles between costa and margin, costal areole, if present, formed by included veinlets |
14 | Lamina pinnatifid or bipinnatifid, lower surface without acicular hairs. |
14' | Lamina simple, lower surface with acicular hairs |
15 | Lamina base truncate, not decurrent into a long wing, scales slightly spreading, phyllopodia obscure, lamina herbaceous or subcoriaceous, included veins more or less immersed and indistinct |
15' | Lamina base narrowly angustate, decurrent into a long wing, scales appressed, or distinctly spreading, phyllopodia more or less elevated, lamina thin-herbaceous, all veins prominent and distinct |
16 | Roots sparsely set, scales densely set, lamina margin sinuate, veins more or less immersed and indistinct |
16' | Roots densely set, scales apically densely set, elsewhere more sparsely set, lamina margin entire, veins prominent and distinct |
17 | Scales in central region glabrous, margin entire or denticulate, phyllopodia more or less distinct, lamina thin-herbaceous, base narrowly angustate, decurrent to a long wing, connecting veins 1-3, between midrib and margin, mainly anadromous |
17' | Scales in central region bearing hairs at least when young, margin dentate, phyllopodia not elevated, lamina herbaceous, base truncate or cuneate, connecting veins 4-7 between midrib and margin, catadromous |