Monographs Details: Didymochlaena
Authority: Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.
Family:Hypodematiaceae
Scientific Name:Didymochlaena
Description:Genus Description - Terrestrial; rhizomes massive, suberect to erect, scaly; fronds clumped, monomorphic, bipinnate; pinnules articulate, oblong, subdimidiate; veins free, forked, not reaching margin; hydathodes present adaxially; costae channelled, lateral ridges with numerous awns 0.5–0.8 mm long, these clustered at base of pinnules; sori terminal on veins, elongate; indusia elliptical, rounded at distal end, cordate or sagittate at base, fixed to vein along medial line; spores bilateral, perispore saccate or folded; x =41.

Discussion:

Type: Didymochlaena sinuosa Desv. [= Didymochlaena truncatula (Sw.) J. Sm.].

Didymochlaena is a monotypic genus, with the single species pantropical and occurring at relatively low elevations. Precise relationships of the genus are unclear, but are probably dryopteroid/ polystichoid. Unpublished molecular work by Cranfill (pers. comm.), using especially the rps4 gene, supports a hypothesis that Didymochlaena may lie near the base of the dryopteroid lineage, but also that it is a rather isolated element within the Dryopteridaceae s.l. Didymochlaena is distinguished by its oblong, entire, subdimidiate segments (pinnules) and elliptical sori, each sorus on both sides of a vein and continuous over the vein at the acroscopic end.