Polypodium virginianum

Rock Polypody
Polypodium virginianum
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Polypodiopsida/Pteridopsida (disputed)
Order:	Polypodiales
Family:	Polypodiaceae
Genus:	Polypodium
Species:	P. virginianum
Binomial name
Polypodium virginianum L.

Polypodium virginianum, commonly known as Rock Polypody, Rock Cap Fern, or Common Polypody, is a small evergreen species of fern native to the Eastern United States and Canada. It generally grows on rocks and occasionally on tree roots in nature.

Description

Polypodium virginianum is a small rhizomatous fern with narrow leaves 8-40 cm long and 3-6 cm wide borne on smooth, scaleless petioles (3-15 cm). Leaves are evergreen, oblong and pinnatifid with acuminate tips. Large, circular sori are prominently featured on the underside of fertile fronds in late summer and autumn. Sporangia are intermixed with long brown glandular hairs. ^[1]

Close up

Numerous sori on the underside of a leaf.

Taxonomy

Polypodium virginianum has several synonyms including: P. vinlandicum A. Love & D. Love, P. vulgare L. var. americanum Hooker, P. vulgare L. var. virginianum (L.) D. C. Eaton^[2]. It is generally treated as distinct, though some have recommended it is equally well treated as a North American variety of the circumboreal P. vulgare.^[1]

This species is an allotetraploid of hybrid origin, the parents being Polypodium appalachianum and P. sibiricum.

Habitat and distribution

P. virginianum typically grows on boulders, cliffs, and rocky slopes and does not need well-developed soil. It is common throughout Eastern North America; its native distribution ranges from Newfoundland to Yukon south to Georgia, Alabama, and Arkansas.^[1]

References

1. ^ ^{a b c} Gleason, Henry A. and Cronquist, Arthur (1991). Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Bronx, NY: The New York Botanical Garden Press. ISBN 0-89327-365-1. 
2. ^ eFloras (2008). Published on the Internet http://www.efloras.org (accessed 22 November 2009) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA. efloras: Polypodium virginianum

• USDA Plants Database: Polypodium virginianum