Gleicheniaceae

Rhizome relatively slender, creeping, protostelic (solenostelic only in Dicranopteris pectinata (WILLD.) UND. of tropical America), in Stromatopteris bearing erect irregularly dichotomous branches which bear the fronds, in all other cases bearing fronds directly; young parts covered with peltate fringed scales (scales otherwise in Stromatopteris) or branched hairs. Fronds unbranched in Stromatopteris, in all other cases branched in fully developed plants, the main rachis bearing a series of pairs of branches, its apex periodically dormant while each successive pair of branches develops; each primary branch often bearing a pair of secondary branches and a permanently dormant apex between them, the process sometimes repeated several times; ultimate branches either bipinnatifid or pinnatifid, the lamina (whether of an ultimate branch, or leaflet of an ultimate branch) cut almost to the costa; veins in lamina-segments pinnate, branches simple or forked, free (in some cases apparently joining a thickened non-vascular margin). Sori of 2—15 or more sporangia, attached to a small receptacle on the surface of a vein (except in Stromatopteris, where each sorus is spread along part of both branches of a forked vein), never at the end of a vein, all sporangia in one sorus developing simultaneously; branched hairs or scales often present with sporangia but no indusium. Sporangia with complete oblique annulus, dehiscing vertically, containing c. 200—800 or more spores. Spores monolete or trilete, smooth, translucent, colourless. Gametophyte (not known in Stromatopteris) at first cordate, then ribbon-like with heavy midrib, finally branching at apex; rhizoids stiff, abundant, usually reddish-brown; two-celled glandular hairs developed by many species in association with archegonia and also on margin; antheridia comparatively large and complex in structure (some more so than others); archegonia with long necks (longest in Gleichenia subg. Gleichenia) directed towards apex of prothallus; no cases of apogamy observed