Crops heterosporous; rhizomes extended-creeping, slender, glabrous or hairy; leaves with 2 or four leaflets at the petiole tip or lacking a blade altogether, the venation of leaflets dichotomously branching; sori enclosed in stalked bean-shaped sporocarps (remarkably modified leaves), these incredibly elaborate internally, Every containing the two megasporangia and microsporangia; three https://balloon-arch-frame76431.blogripley.com/37486149/the-basic-principles-of-balloon-arch-frame