Specimen record
Rock Polypody
Polypodium virginianum
Description
A small, tough evergreen fern that grows in dense mats on the surface of rocks and boulders, rooted in thin accumulations of humus and moss. Rock polypody is the characteristic fern of shaded rock outcrops in New England forests. The once-pinnate fronds are leathery and stay green through winter. Large round sori on the frond underside lack a protective covering (indusium), distinguishing this genus from most other ferns.
Identification tips
- 1Small evergreen fern growing directly on rock surfaces in mats
- 2Leathery, once-pinnate fronds 10–25 cm long with rounded to blunt-tipped pinnae
- 3Large, round, orange-brown sori on underside of pinnae — no indusium (covering)
- 4Rhizome creeping along the rock surface, often partially visible
- 5Found on shaded, moss-covered rock outcrops and boulders — not on soil
Specimen & preservation notes
Peel a section of frond with attached rhizome from the rock surface. The evergreen fronds press flat easily. Show the sori on the underside — mount one frond face-up and one face-down on the herbarium sheet. Collect at any time of year since the fronds are persistent.
Habitats
Collection calendar
| Wk | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov |
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Collection notes
Season check
No flowering records for this species yet.
Flowering records: 0 iNaturalist observations, Massachusetts · Nearby: 370 observations within 25 km