2. Polypodium virginianum L. (common polypody) Pl.
15f,g; Map 55
P. vulgare L. var. virginianum (L.) A.A. Eaton
Rhizome scales orangish brown, concolorous or with a somewhat darker central
stripe, lanceolate, the margins slightly toothed. Leaves 4–40 cm long, the
petioles green to light brown, grooved on the upper surface, glabrous. Leaf
blades herbaceous to somewhat leathery, lanceolate, tapering to the tip, the
lobes with rounded to somewhat pointed tips and entire to slightly toothed
margins, glabrous. Sporangia intermingled in the sorus with long, club-shaped,
glandular hairs, with 64 spores. 2n=148. June–August.
Most common in the eastern portion of the Ozark Division, locally west to Laclede County
and north to Marion County (eastern U.S.
Ledges and crevices of bluffs and boulders, on sandstone, chert, granite, and
other acidic substrates.
The relationships among the American and European species of the P. vulgare
complex were first elucidated by Shivas (1961). True diploid P. vulgare
occurs in Europe. More recently, Haufler and
his associates (Haufler and Windham, 1991; Haufler and Wang, 1991) have shown
that P. virginianum is a fertile, tetraploid derivative of past
hybridization between two closely related diploid species, P. appalachianum
Haufler & Windham and P. sibiricum Sipliv., neither of whose ranges
extends to Missouri.