Vegetation heterosporous; rhizomes extensive-creeping, slender, glabrous or hairy; leaves with 2 or 4 leaflets on the petiole suggestion or missing a blade altogether, the venation of leaflets dichotomously branching; sori enclosed in stalked bean-formed sporocarps (really modified leaves), these very sophisticated internally, each containing equally megasporangia and microsporangia; ... https://marcoubiou.blazingblog.com/36643860/facts-about-balloon-arch-frame-revealed