Dryopteris cristata

Dryopteris cristata (L.) A. Gray

Local names: crested wood fern

A circumboreal species of the ne U.S. and s Canada, was long erroneously reported for TX (Correll 1956; Wherry 1964; Correll & Johnston 1970; Correll & Correll 1972), but does not occur in the state (Thomas et al. 1973; Peck & Peck 1988; Peck 2000; Diggs et al. 2006; Mink et al. 2011a); the erroneous reports were based on incorrect identification of the 1925 Palmer collection. A detailed discussion and photographs of the Palmer specimens involved (some were mixed collections with Osmundastrum cinnamomeum) can be found in Mink et al. (2011a). Dryopteris cristata is easily recognized in the field because the upper fertile pinnae are held horizontally (like an open venetian blind) in contrast to the situation in D. celsa, which has both fertile and sterile pinnae held parallel to the plane of the blade (like a closed venetian blind). Sporulating summer–fall. [D. goldiana (Hook. ex Goldie) A. Gray subsp. celsa W. Palmer] Dryopteris celsa is a fertile allotetraploid resulting from hybridization between D. goldiana (Hook. ex Goldie) A. Gray (goldie’s wood fern) and D. ludoviciana (Walker 1962; Montgomery & Wagner 1993). It has been proposed that the two parent species, which no longer occur together, were pushed into contact by the climatic change accompanying the last glacial maximum, only ca. 18,000 years ago. If this is the case the species is quite young in terms of geologic time (Taylor 1984; Moran 2004). In various parts of its range, D. celsa is known to hybridize with six other species. The common name, log fern, is derived from the tendency of the species to grow on logs or humus (Snyder & Bruce 1986). Thomas et al. (1973) noted “The plants are best located in midwinter and late winter, when the swamps are relatively clear of foliage. The previous year’s fronds lie upon the ground but will usually remain more or less evergreen and excellent specimens may be obtained.” Because of its rareness and extremely limited distribution in the state, we consider this species to be of conservation concern in TX.

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