Physematium

Ponce, M. Mónica, Gorrer, Daniel A. & Arana, Marcelo D., 2025, Hidden and neglected taxa inside a collective taxon: taxonomic revision of Woodsiaceae in the Southern Cone of South America, Willdenowia 55 (1), pp. 29-49 : 34

Key to the species of Physematium in the Southern Cone

1. Fronds gracile, pendulous; pinnae subremote to remote; last pinna segments (pinnules) toothed, with rounded to obtuse teeth; pinnule bases broadly decurrent to rachis, rachis becoming winged; spores reticulate, without folds.............. 1. P. hieronymi

– Fronds erect to patent; pinnae approximate to subremote; last segments (or pinnules) slightly to strongly crenulate or bicrenulate; pinnule bases of last segments or pinnules adnate or slightly decurrent to rachis; spores reticulate-folded, with conspicuous folds.................................... 2

2. Stipes robust, 1.5–2 mm in diam., not brittle; stipe scales dull, concolorous or partly bicolorous, light brown, orange or reddish, triangular, broadly triangular or ovate-triangular, when bicolorous, with sclerotic, dark brown centre sections, and with broad, membranous margin, hyaline to light brown, with distant hairs or fimbriae on margin, apex attenuate with a terminal hair; indusium 3-lobed; spores yellowish, with numerous, small, complete and incomplete reticles........................... 3. P. montevidense

– Stipes thin, 0.5–1 mm in diam., notably brittle; stipe scales shiny, strongly bicolorous, dark brown to blackish, sclerotic, linear-triangular or subulate, with narrow or wide, membranous, pale brown, entire or sparsely pilose margin; indusium 1–3-lobed; spores brownish or yellowish, if yellowish, never with small reticles.................................. 3

3. Plants more than 20 cm tall; stipes dark brown or dark purple to burgundy proximally, sometimes up to or through rachis; laminae pinnate-pinnatifid to almost bipinnate; pinnae proximate, triangular, acute apex, fertile ones usually with recurved margin; indusia with 1–3 strap-shaped lobes, usually 1 lobe more developed than others; spores yellowish with few and large, complete and incomplete reticles................................ 2. P. jujuiense

– Plants to 15 cm tall; stipes straw-coloured or stramineous, rarely darkened only very proximally; laminae pinnate; pinnae subremote, oblong or oblongtriangular, apex rounded, fertile ones usually with flat or slightly curved margin; indusia divided into 2 or 3 strap-shaped lobes at maturity; spores brownish with numerous and small, complete and incomplete reticles........................... 4. P. pallidum