Dryopteris celsa and D. clintoniana in New Jersey

Abstract

Since the publication of Ferns of New by Chrysler and Edwards (1947), a great deal has been learned about the relationships of the eastern American Wood Ferns, Dryopteris. The work begun by Manton (1950) has been followed up by Walker (1959, 1961, 1962), and especially by Wagner and his coworkers (1971 and other references). Although some problems still remain to be resolved, the relationships are reasonably well understood (Wagner, 1971). Except for D. celsa, the distributions of the species are generally known, but those of the hybrids (especially those involving D. celsa and D. clintoniana) are known in local areas only, e.g., Michigan (Wagner & Hagenah, 1962; Wagner, Wagner & Hagenah, 1969), Virginia (Wagner, 1963; Wagner & Wagner, 1966), New York (Wagner & Wagner, 1965), and Ontario (Britton & Soper, 1966). Dryopteris celsa is primarily a southern lowland plant of the piedmont and coastal plain, although its distribution inland may not be fully known. Isolated populations are known in northern New York and Michigan (Wagner, 1971). Dryopteris clintoniana, on the other hand, is a northern and upland plant, and rarely is found south of the Wisconsin glacial boundary (Wagner, Wagner & Hagetah, 1969). Dryopteris species and hybrids are abundant in the northern part of New Jersey. This area should be one of overlap for D. celsa and D. clintoniana, since the glacial boundary and the upland-lowland boundary both occur here. Only D. clintoniana has been previously reported, except for a publication on material used for chromosome studies by Wagner (1971), in which hybrids involving D. celsa were detected. No recent field work involving Dryopteris populations has been reported, and no other chromosome counts have been made, hence the presence of D. celsa in New Jersey is undocumented. The purpose of this paper, therefore, is to investigate the distribution of Dryopteris celsa and D. clintoniana in New Jersey.