The World Flora Online

Plants perennial, terrestrial, on rock, or often epiphytic, erect, arching, or occasionally pendent. Stems long- to short-creeping, branched or not, bearing scales and few to numerous roots, usually dictyostelic. Leaves monomorphic to dimorphic, circinate in bud. Petiole usually articulate at base [rarely nonarticulate, as in Loxogramme ], lacking scales or sometimes scaly, with usually 3 vascular bundles. Bladesimple to often pinnatifid, pinnatisect, or pinnate, infrequently moredivided; rachis grooved or not adaxially. Veins free (and simpleto several times forked) to often anastomosing in complex systems, areoleswith or without included veinlets. Indument on blade absent, orpetiole, rachis, costae, and sometimes blade tissue usually bearing hairs(these often septate and with reddish crosswalls) and/or scales. Soriborne abaxially on veins, round to oblong, occasionally elongate, rarelymarginal, rarely covering surface; paraphyses present or absent; sporangiawith stalk of 2 or 3 rows of cells; indusia absent. Spores usuallytransparent or yellowish (rarely greenish), all 1 kind, bilateral, monolete[rarely trilete, as in some Loxogramme], surface most often smooth,tuberculate, verrucose, or granulate, occasionally spiny, 64 per sporangium(spores globose and 32 per sporangium in apogamous spp.). Gametophytesgreen, aboveground, cordate or elliptic, glabrous or sometimes glandular;archegonia and antheridia borne on lower surface, antheridia 3-celled.

Source: [
• 3
]. 

Plants mostly epiphytic and epilithic, a few terrestrial. Rhizomes shortly to long creeping, dictyostelic, bearing scales. Fronds monomorphic or dimorphic, mostly simple to pinnatifid or 1-pinnate (uncommonly more divided); stipes cleanly abscising near their bases or not (most grammitids), leaving short phyllopodia; veins often anastomosing or reticulate, sometimes with included veinlets, or veins free (most grammitids); indument various, of scales, hairs, or glands. Sori abaxial (rarely marginal), orbicular to oblong or elliptic, occasionally elongate, or sporangia acrostichoid, sometimes deeply embedded, sori exindusiate, sometimes covered by caducous scales (soral paraphyses) when young; sporangia with 1-3-rowed, usually long stalks, frequently with paraphyses on sporangia or on receptacle; spores hyaline to yellowish, reniform, and monolete (non-grammitids), or greenish and globose-tetrahedral, trilete (most grammitids); perine various, usually thin, not strongly winged or cristate. Mostly x = 35, 36, 37.

Source: [
• 4
]. 

Sori laminar, borne in 1–several rows on each side of the costa, without an indusium; sporangia thin-walled and with a well developed vertical annulus interrupted by the stalk; spores (32)64, bilateral; rhizome scaly; petiole eventually abscising to leave a short projection on the rhizome; blade simple or once pinnate, glabrous or with short hairs or few to many scales; veins free or often in part reticulate. 45/350+. Family in the past often broadly defined to include the Adiantaceae, Aspleniaceae, Blechnaceae, Dennstaedtiaceae, and Onocleaceae.

Source: [
• 10
]. 

Epiphytes, rarely terrestrial, with creeping rhizomes containing a ring of small vascular bundles; scales peltate, clathrate or not

Source: [
• 1
]. 

Terrestrial, epiphytic or less often on rocks Rhizomes short to long and creeping with basifixed pseudopeltate or peltate clathrate opaque or hyaline entire toothed or ciliate scales

Source: [
• 2
]. 

Fougères généralement épiphytes , rarement terrestres, à rhizome contenant un anneau de faisceaux vasculaires. Écailles le plus souvent peltées. Frondes en 2 rangées à la partie supérieure du rhizome, et articulées (à part Sténochlaena). Fronde entière ou pennée, à nervation réticulée, aréoles à nervilles incluses . Sores sans indusie (quelquefois portant des paraphyses aplaties), arrondis, ou allongés, quelquefois enfoncés dans des cavités, ou acrostichoides. Sporanges à long pied, et 12-16 cellules en U.

Source: [
• 13
].