Crepidomanes intricatum (Farrar) Ebihara & Weakley. Grotto-felt, Appalachian Trichomanes, Weft Fern. Hab: On ceilings or back walls of grottoes, especially in humid gorges or near or behind waterfalls. Dist: Rather widespread in e. North America, from NH, VT, w. NY, OH, IN, and IL south to NC, nw. SC, n. GA, and n. AL.

Origin/Endemic status: Native

Taxonomy Comments: While Crepidomanes intricatum is difficult to morphologically distinguish from gametophytes of Vandenboschia boschiana or Didymoglossum petersii; the electrophoretic and phytogeographic evidence of Farrar (1992) leave little question that it should be considered a distinct species. Although Farrar (1992) found that 30 of 30 populations of Trichomanes (s.l.) gametophytes "east of the Mississippi River that were not within or adjacent to sporophyte populations of T. boschianum or T. petersii" were "C. intricatum," the absence of sporophytes should be considered to provide only a presumptive or likely identification of gametophytes. Farrar (1992) also showed that independent gametophytes in AR were those of Vandenboschia boschiana and Didymoglossum petersii. Farrar (1992) points out the "intriguing possibility that somewhere in the Appalachian Mountains sporophytes of this species may yet exist." Probably the most likely area in which to search for the sporophyte generation of Crepidomanes intricatum is the escarpment gorge region of NC, SC, and GA near Highlands, NC, where topography, waterfalls, and the highest rainfall east of the Cascade Mountains combine to create microclimatic conditions that have favored the relict survival of numerous species of mosses, liverworts, and ferns. Any filmy-fern sporophyte which differs from known eastern North America species of Hymenophyllaceae should be investigated carefully. Vittaria appalachiana and Hymenophyllum tayloriae gametophytes differ from Crepidomanes intricatum in being thallose rather than filamentous. Ebihara, Farrar, & Ito (2008) reported that Crepidomanes intricatum shares its chloroplast genome with the Asian triploid Crepidomanes schmidtianum (Zenker ex Taschner) K. Iwatsuki var. schmidtianum, widely distributed in temperate e. Asia (China, Japan, Nepal, Bhutan, n. India). Further studies are underway to determine the relationship of the two. Given the probable different ploidy and apparent long-term separation of the Appalachian plant from the east Asian, it seems best to treat them as specifically distinct.

Synonymy: = Il, K3, K4, NY, Va, Weakley et al (2011); = gametophyte with – RAB; = n/a – C, F; = Trichomanes intricatum Farrar – FNA2, K1, NE, Pa, Tn; = Vandenboschia species 1 – Ebihara et al (2006)

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Heliophily: 1