Scientific name: DennstaedtiaceaeEnglish name: Vietnamese name: Ráng đàn tiếtOther name:
Dennstaedtiaceae is one of fifteen families in the order Polypodiales, the most derived families within monilophytes (ferns). It includes the world's most abundant fern, Pteridium aquilinum (bracken). Members of the order generally have large, highly divided leaves and have either small, round intramarginal sori with cup-shaped indusia (e.g. Dennstaedtia) or linear marginal sori with a false indusium formed from the reflexed leaf margin (e.g. Pteridium). The morphological diversity among members of the order has confused past taxonomy, but recent molecular studies have supported the monophylogeny of the order and the family . The reclassification of Dennstaedtiaceae and the rest of the monilophytes was published in 2006, so most of the available literature is not updated.
Small to large terrestrial ferns (very rarely with a climbing rhizome), the rhizome wide-creeping underground, branching dichotomously or sympodially with fronds arising from the branches, less often erect and radial, solenostelic or dictyostelic, tips with simple hairs, less often pluricellular hairs, rarely with dark, non-clathrate, non-peltate scales. Fronds long-stipitate, sometimes scrambling, the stipes not articulate to the rhizome, vascular tissue mostly U-shaped, lamina mostly pinnately decompound and finely divided, less often 1 - 2-pinnate, veins free simple or 1 - several times forked, less often anastomosing without free included veinlets; little, if any, sterile/fertile dimorphism. Sori terminal on the veins, small and round or elongate and spreading along a vascular commisure uniting the vein endings, often indusiate, the indusium opening towards the margin, sometimes cup-shaped, or 2-valved with the reflexed leaf margin (sometimes scariose) forming a false indusium, sometimes the true and/or false indusium absent, annulus longitudinal, interrupted, stalk slender and 2-seriate, paraphyses present or absent; spores trilete, tetrahedral, sometimes monolete, lacking a perispore