stems with polycyclic dictyosteles, apices (and usually petiole bases) covered with large scales, sometimes also with trichomidia (scurf = small scales) or hairs; leaves usually large (to 5 m); petioles with obvious, usually discontinuous pneumathodes in two lines; blades 1–3-pinnate (rarely simple); veins simple to forked, free, rarely anastomosing (mostly in some Cyathea); sori superficial (abaxial) or terminal on the veins and marginal or submarginal (Hymenophyllopsis), round, exindusiate, or indusia saucer-like, cup-like, or globose and completely surrounding sporangia, or bivalvate (Hymenophyllopsis); sporangia maturing gradately, with oblique annuli; receptacles raised; paraphyses usually present; spores tetrahedral, trilete, variously ornamented; gametophytes green, cordate; x = 69 (Hymenophyllopsis not yet counted).
Systematic remarks
Cyatheoids, scaly tree ferns; incl. Alsophilaceae, Hymenophyllopsidaceae.
