Grammitidaceae

Abstract

Epiphytic, sometimes terrestrial or rupestral ferns, with creeping to erect, simple or ± branched solenostelic stem usually bearing scales, occasionally glabrous. Petiole usually non-articulated to rhizome, terete, with a single vascular strand. Leaf usually bearing unicellular or multicellular, occasionally glandular, hairs which sometimes have unicellular or multicellular outgrowths. Lamina simple to tripinnate; veins free or occasionally casually anastomosing without free included veinlets, sometimes ending in a thickened apex or hydathode which may bear a white scale. Sori exindusiate, round or elongate, on the abaxial side of the lamina or submarginal, sometimes sunken in laminar tissue on the abaxial surface or at or near the margin, sometimes protected by the lamina being folded over them; receptacular appendages sometimes present; sporangia many, sometimes bearing hairs near the annulus, maturing at different times; annulus longitudinal, bow of c. 7–20 cells; stalk usually of one row of cells. Spores usually 64, sometimes 16 or 32 per sporangium, chlorophyllous, thin-walled, usually globose to tetrahedral with trilete laesura, papillate with scattered spherical deposit, sometimes somewhat verrucate, somewhat echinate in Calymmodon.