1 | Water plants; sporangia borne singly and protected by reflexed edges of the lamina. |
1' | Land plants; sporangia in sori or more or less acrostichoid. |
2 | Rigid hairs or bristles on rhizome and bases of stipes. |
2' | Scales on rhizome and bases of stipes. |
3 | Fronds bipinnate, leaflets more or less lobed |
3' | Fronds simple or simply pinnate, or palmate with entire leaflets. |
4 | Veins anastomosing only near edge of lamina; fronds simple or palmate; paraphyses (if present) with distinctive apikal cell |
4' | Veins anastomosing throughout lamina; fronds pinnate, trilobed or simple; paraphyses always abundant, hair-like, of many cells, apical one not different from the rest. |
5 | Sori broad, elongate, parallel to costa and edge, or more or less spreading along the veins. |
5' | Sori in submarginal grooves, edges of grooves of equal thickness (Schizoloma sensu Copel.). |
6 | Lower surface of fronds covered with white or yellow powder. |
6' | Lower surface of fronds not covered with such powder. |
7 | Sori along whole length of veins on lower surface |
7' | Sori at ends of veins, protected by reflexed lobes of margin |
8 | Sori elongate (continuous or broken) along margins of lamina and protected by reflexed margin. |
8' | Sori otherwise. |
9 | Fronds much dissected, the ultimate lamina-lobes small and connected by a narrow wing. |
9' | Fronds, if much branched, having quite distinct leaflets not joined by a wing. |
10 | Fertile lobes much broader than sterile, the whole of each margin bearing a broad thin reflexed indusium |
10' | Fertile lobes not much broader than sterile, reflexed margin not continuous along larger fertile lobes nor very broad |
11 | Fronds simple and lobed, or deeply pinnatifid; sori quite continuous along edge |
11' | Fronds branched with distinct stalked leaflets |
12 | Sori elongate along all or most of the veins. |
12' | Sori otherwise. |
13 | Fronds simple |
13' | Fronds pinnate or bipinnate |
14 | Sori on lower surface, spreading a little along the veins |
14' | Sori at ends of veins. |
15 | Sori on surface of reflexed marginal flaps |
15' | Sori at ends of veins, sometimes more or less protected by reflexed marginal flaps |