Polypodium glycyrrhiza
Polypodium calirhiza
licorice fern, licorice polypody fern
licorice fern, nested polypody
not whitish pruinose, slender to moderately stout, to 6 mm diam., intensely sweet, licorice-flavored;
scales concolored, brown or slightly darker near point of attachment, lanceolate to lanceolate-ovate, symmetric, margins entire.
rarely whitish to glaucous, moderately stout to slender, to 8 mm diam., acrid- or slightly sweet-tasting;
scales concolored brown or slightly darker near point of attachment, lanceolate-ovate, symmetric, margins entire to erose.
to 75 cm.
to 70 cm.
usually slender, 0.5–2 mm diam.
usually slender, to 3 mm diam.
lanceolate-ovate to oblong, pinnatifid, widest near middle or just below, to 16 cm wide, herbaceous, rarely slightly leathery;
rachis sparsely scaly to glabrescent abaxially, puberulent adaxially;
scales linear, usually less than 3 cells wide.
lanceolate-ovate to oblong, pinnatifid, widest below middle or occasionally at base, to 16 cm wide, leathery to herbaceous;
rachis sparsely scaly to glabrescent abaxially, puberulent adaxially;
scales lanceolate-ovate, usually more than 3 cells wide.
linear to oblong, less than 12 mm wide;
margins serrate;
apex acute to attenuate;
midrib puberulent adaxially.
linear-lanceolate to oblong, usually less than 15 mm wide;
margins conspicuously serrate;
apex obtuse to acute;
midrib puberulent adaxially.
midway between margin and midrib or slightly closer to midrib, usually less than 3 mm diam., circular to oval when immature.
midway between margin and midrib or slightly closer to midrib, usually less than 4 mm diam., oval when immature.
less than 58 µm, verrucose, with surface projections less than 3 µm. 2n = 74.
more than 58 µm, verrucose, surface projections less than 3 µm. 2n = 148.
free.
weakly to moderately anastomosing, some to many segments lacking areoles.
absent.
absent.
Polypodium glycyrrhiza
Polypodium calirhiza
Polypodium glycyrrhiza hybridizes with P. calirhiza and with P. hesperium to produce sterile triploids with misshapen spores. Polypodium glycyrrhiza was involved in the origin of both of these allotetraploid species, and some individuals can be difficult to identify. Free versus anastomosing venation distinguishes this species from P. calirhiza; the presence of adaxial hairs on the rachis separates it from P. hesperium. An additional character for distinguishing these taxa is spore length, which is less than 58 µm in diploid P. glycyrrhiza and more than 58 µm in the two tetraploid species. Reports of P. glycyrrhiza occurring in Arizona (T. Reeves 1981; D. B. Lellinger 1985) are based on misidentified specimens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Although originally considered a cytotype of Polypodium californicum, P. calirhiza is an allotetraploid involving P. californicum and P. glycyrrhiza (S. A. Whitmore and A. R. Smith 1991) and therefore should be treated as a distinct species. Some individuals of P. calirhiza can be difficult to distinguish from the two parental species (see comments under P. californicum and P. glycyrrhiza); most collections can be identified based on a combination of blade shape, venation pattern, spore size, and geographic distribution. Polypodium calirhiza hybridizes with P. glycyrrhiza to produce sterile triploid plants with misshapen spores.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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