Woodwardia virginica

Woodwardia virginica (L.) Small
(of Virginia, Linnaeus giving many plants from the eastern U.S. this epithet)

Local names: Virginia chain fern

Leaves numerous, 50–100 cm long; petioles straw-colored to greenish above, dark reddish brown to purplish or nearly black at base; pinnae in 12–23 pairs, the middle pinnae 1–3.5 cm wide, the veins anastomosing to form a single row of areoles near midvein; rachis straw-colored, sometimes darkly so; sori covering only a small part of the blade surface; 2n = 70 (Cranfill 1993b). Low areas; primarily Pineywoods and n edge of Gulf Prairies and Marshes (Orange Co.—Turner et al. 2003) disjunct w to Bastrop (W.R. Carr & E.A. Kutac 7740, BRIT), Lee (TAMU), Gonzales (Tharp s.n. 1935, Ottine, BRIT, TEX-LL), and Milam (TEX-LL) cos. on w margin of Post Oak Savannah; se Canada and e U.S. from ME s to FL w to IL, AR, and TX; also Bermuda. Sporulating Apr–Dec. This species has sometimes been segregated into the genus Anchistea [as A. virginica (L.) C. Presl]. It has a long fossil history (e.g., Pigg & Rothwell 2001) and fossils from the middle Miocene (ca. 14 mya) are “structurally identical” to modern W. virginica. Pigg and Rothwell (2001) note that this species adds “additional data to our growing realization that some homosporous pteridophytes display exceptional species longevity.” In TX this species is found primarily in the far e part of the state in the Pineywoods and then disjunct to 4 counties further w. These w populations are presumably relicts of more humid conditions in the past that have been able to survive in isolation since Ice Age times due to unique bogs and wetlands associated with the sandy, porous Carrizo Formation. For example, in Milam Co. (L.C. Taylor 3574, TEX-LL) the species was found in a “peat bog.” Likewise, the southwestern most location for the species, Gonzales Co., is from the Ottine wetlands—a relict spring-fed ecosystem. Numerous other mesic species are disjunct to similar such wet microhabitats in otherwise rather dry inhospitable environments in c TX, and are thought to be relicts of Ice Age times (see page 36). Virginia chain fern can be confused when sterile with the superficially similar Osmundastrum cinnamomeum, cinnamon fern. However, it can be “distinguished at some distance by the dark brown base of the petiole, mostly darker rachis, and by the fronds being well spaced rather than clump forming” (Nelson 2000). When fertile, the two species are dramatically different (in Osmundastrum the fertile pinnae are completely different from the sterile—not very leaf-like, with no expanded pinnae, and densely tomentose).

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