Adiantaceae

Small to medium-sized ferns, usually growing amongst rocks, often xerophytic, other species confined to RF. Rhizomes erect or creeping, dictyostelic or more usually solenostelic, clothed with bristle-like or woolly hairs or more usually with scales which range from fuscous or ferruginous to black with a paler border; the paleae intermixed with silky hairs in some genera. Stipes stramineous or castaneous or maroon or brown or black, often glossy, glabrous to densely scaly and/or hairs, grooved above or terete, not articulated to the rhizome. Main rhachis grooved above or terete. Fronds uniform or rarely dimorphic, simple, 1–5-pinnate or -pedate or sometimes palmate, thin to coriaceous, glabrous, hairy or scaly, covered with waxy powder in some genera. Ultimate segments equilateral or unilateral, dimidiate or trapeziform or cuneate-flabelliform or linear or lanceolate or ovate to roundish, articulated or non-articulated. Veins usually free, sometimes anastomosing, without free included veinlets in the areolae. Sori superficial or submarginal in some genera, but appearing to be marginal in the genera occurring in New South Wales, exindusiate or with a false indusium, rarely with a vascular commissure, borne on the distal vein-endings and sometimes between them, then either rounded or confluent into ± continuous, intramarginal, linear or oblong sori, otherwise spreading inwards along the veins and sometimes occurring in the spaces between them, rarely monangial. Indusium false, either; a reflexed, modified, marginal flap bearing and covering the sorus (Adiantum) (Fig. 17); or the reflexed, continuous veinless, ± modified margin of the ultimate segment or in other genera the margin flat and unmodified as a false indusium. Paraphyses present in some genera, sometimes clavate. Sporangia mixed, usually large; the pedicel short to subsessile or elongated, with 3–6-rows of cells; the annulus including 14–24 indurated cells. Spores globoso-tetrahedral or tetrahedral, rarely bilateral, smooth or reticulate-spinose or corrugated or otherwise ornamented, without a perispore. c. 28 gen. cosmop., often in dry country.