Polypodium virginianum
Polypodium californicum
common polypody, polypode de virginie, rock polypody, tripes-de-roches
California polypody
often whitish pruinose, slender, to 6 mm diam., acrid-tasting;
scales weakly bicolored, lanceolate, contorted distally, base and margins light brown, sometimes with dark central stripe, margins denticulate.
dull or inconspicuously glaucous, moderately stout, to 10 mm diam., acrid or bland-tasting;
scales uniformly brown or slightly darker near point of attachment, lanceolate-ovate, symmetric, margins entire to erose.
to 40 cm.
to 70 cm.
slender, to 2 mm diam.
usually slender, to 3 mm diam.
oblong to narrowly lanceolate, pinnatifid, usually widest near middle, occasionally at or near base, to 7 cm wide, somewhat leathery;
rachis sparsely scaly to glabrescent abaxially, glabrous adaxially;
scales lanceolate-ovate, usually more than 6 cells wide.
deltate to lanceolate-ovate, pinnatifid, usually widest near base, to 20 cm wide, leathery to herbaceous;
rachis sparsely scaly to glabrescent abaxially, puberulent adaxially;
scales deltate to ovate, usually more than 10 cells wide.
oblong, less than 8 mm wide;
margins entire to crenulate;
apex rounded to broadly acute;
midrib glabrous adaxially.
linear-lanceolate to oblong, usually less than 15 mm wide;
margins serrate;
apex widely obtuse to rarely attenuate;
midrib puberulent adaxially.
midway between margin and midrib to nearly marginal, less than 3 mm diam., circular when immature.
midway between margin and midrib or slightly closer to midrib, usually less than 3 mm diam., oval when immature.
more than 52 µm, tuberculate, surface projections more than 3 µm tall.
less than 58 µm, verrucose, with surface projections to 3 µm. 2n = 74.
free.
weakly to conspicuously anastomosing, most segments containing several areoles, often forming 1 row.
present, usually less than 40 per sorus, heads covered with glandular hairs.
absent.
= 148.
Polypodium virginianum
Polypodium californicum
Traditionally, two cytotypes have been recognized within Polypodium virginianum (I. Manton and M. Shivas 1953). Recent research has demonstrated that the tetraploid cytotype, which properly bears the name P. virginianum (R. Cranfill and D. M. Britton 1983), is an allopolyploid produced by hybridization between the diploid cytotype (here called P. appalachianum) and P. sibiricum (C. H. Haufler and M. D. Windham 1991; C. H. Haufler and Wang Z. R. 1991). Although sometimes similar to its diploid parents in overall leaf morphology, P. virginianum has consistently larger spores, typically more than 52 µm (see additional comments under P. appalachianum and P. sibiricum). Frequent hybridizations between P. virginianum and P. appalachianum form morphologically intermediate, triploid individuals with misshapen spores. Sterile triploids also result from hybridization between P. virginianum and P. sibiricum.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
R. M. Lloyd and F. A. Lang (1964) recognized two cytotypes within Polypodium californicum. The tetraploid has proved to be an allopolyploid involving P. californicum and P. glycyrrhiza and is treated here as a separate species, P. calirhiza, following S. A. Whitmore and A. R. Smith (1991). Polypodium californicum can be confused with P. calirhiza, but it usually can be distinguished by blade shape, venation, spore size, and geographic distribution. D. S. Barrington et al. (1986) reported that spores of northern populations of P. californicum can be as large as those of P. calirhiza, but the former species has veins forming more areoles per segment than does the latter.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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