Claytosmunda (Y. Yatabe, N. Murakami, & K. Iwatsuki) Metzgar & Rouhan Rouhan.
A monotypic genus, a perennial fern, of e. North America and e. Asia.
ID notes:Claytosmunda is the most "upland" and least robust of our Osmundaceae species. Fertile leaves of Claytosmunda are unique in the placement of brown (later shriveled) spore-bearing pinnae in the middle of the blade, with sterile, green pinnae above and below the fertile pinnae. Sterile plants (which are frequent, and entire populations sometimes lack fertile plants) can closely resemble sterile plants of Osmundastrum cinnamomeum, but can be told by the lack of a tuft of hairs on the lower side of the junction of each pinna to the rachis. Additionally, Claytosmunda claytoniana has a smoother gestalt and overall rounder pinna and pinna lobe tips, while Osmundastrum cinnamomeum has a hairier gestalt and overall more pointed pinna tips and pinna lobe tips.
Ref: Kramer & Green (1990); Lellinger (1985); Metzgar et al. (2008); PPG I (2016); Schneider et al. (2015); Tsutsumi et al. (2011); Whetstone & Atkinson (1993) In Flora of North America Editorial Committee (1993b); Yatabe, Nishida, and Murakami (1999); Zhang, Iwatsuki, & Kadokawa in FoC (2013). Show full citations.