Dennstaedtiaceae Lotsy

Terrestrial or rupestral ferns. Rhizomes often long-creeping or occasionally short-creeping, usually bearing multicellular hairs, or rarely scales and unicellular hairs (in Histiopteris). Fronds monomorphic, not articulated to rhizome. Laminae usually 2–5-pinnate, rarely 1-pinnate (not NZ), anadromous, herbaceous or coriaceous, usually hairy or rarely glabrous, lacking scales. Veins usually free or rarely anastomosing without free included veinlets. Sori round, or extending laterally, or almost continuous around the lamina margin, superficial or on a slightly raised receptacle, borne on abaxial surface, marginal or submarginal; paraphyses present or absent; indusia ovate and attached at base, or half-cup- or cup-shaped and attached at base and sides, or with a pseudoindusium (formed from the modified recurved lamina margin) sometimes also with an inner indusium, or indusia absent; sporangial maturation mixed. Sporangia with vertical or slightly oblique annulus, usually 64 spores per sporangium. Homosporous; spores monolete or trilete, lacking chlorophyll; perispores variably sculptured.

A family of 11 genera and about 265 species (PPG 1 2016; Shang et al. 2018; Schwartsburd et al. 2020). Kramer (1990) included the Lindsaeoid ferns within the Dennstaedtiaceae, recognising a broad family of about 16 genera. However, molecular analyses (Wolf et al. 1994; Wolf 1995; Der et al. 2009; Lehtonen et al. 2010) showed that the two groups belonged to different clades and should be recognised as the separate families Dennstaedtiaceae and Lindsaeaceae. Smith et al. (2006) listed the genera Blotiella, Coptodipteris, Dennstaedtia, Histiopteris, Hypolepis, Leptolepia, Microlepia, Monachosorum, Oenotrichia, Paesia, and Pteridium within Dennstaedtiaceae, but Yan et al. (2013) reduced the monotypic Coptodipteris to synonymy in Dennstaedtia. Perrie et al. (2015) confirmed that Oenotrichia belongs in the Dennstaedtiaceae, but also showed that Dennstaedtia and Saccoloma are both not monophyletic. Dennstaedtia forms two distinct clades within Dennstaedtiaceae, while Saccoloma forms one clade within Dennstaedtiaceae and one outside. Further work is needed to delimit the genera within the family.

The Dennstaedtiaceae comprises predominantly terrestrial or scandent ferns with long-creeping rhizomes, mostly 2–5-pinnate laminae bearing multicellular hairs, marginal or submarginal sori that are either discrete or elongated around the lamina edge, and indusia that are either attached at the base and open towards the margin or are formed from the inrolled lamina margin. The sporangia have a vertical annulus. Many of the New Zealand species are opportunist species of disturbed areas.