Dryopteris filix-mas
Dryopteris filix-mas (L.) Schott
(Latin: filix, fern and mas, male or masculine, = male fern, in reference to the less delicate or less graceful appearance of this species in comparison with the superficially similar Athyrium filix-femina)
Local names: lady fern, male fern
Rhizomes suberect to erect; leaves monomorphic, dying back in winter; petioles less than ¼ length of total leaf, with scales at least at base, the scales of 2 distinct types (1 broad, scalelike and 1 hair-like), brown, usually quite obvious; leaf blades 1-pinnate-pinnatifid to 2-pinnate-pinnatifid at base, ovate-lanceolate, ca. 22–90+ cm long, with texture firm but not leathery, basal basiscopic pinnule and basal acroscopic pinnule ca. equal; sori midway between midvein and margin of ultimate leaf segments;2n = 164 [?] (Montgomery & Wagner 1993). On ledges, bluffs, cliffs, and moist woods (Yarborough & Powell 2002); in TX known only from the Davis Mts., Jeff Davis Co. (Correll 15003, 34969; L.C. Hinkley 173; Warnock 7454, 23020, 23094, all TEX-LL; L.C. Hinkley s.n. 1936, P. Manning et al. 3395, SRSC; B. McBride s.n., BRIT, HCP, “Dark shaded crevices of large granite boulders, Pile of Rocks”; D. Benham & C.M. Rowell 172, BRIT; E.J. Palmer 32035, 34042, 34262, MO); ne U.S. and adjacent Canada and widespread in the w U.S. and adjacent Canada; also Mexico (Coahuila), Asia, and Europe. Sporulating May–Nov. [Polypodium filix-mas (L.) Schott] Montgomery and Wagner (1993) noted that this species has been considered to be both an auto- and an allopolyploid, that it “may be composed of at least two closely related taxa,” and that its taxonomy “is not well understood.” They further observed that plants “in the northeast and northwest are tetraploid. These differ morphologically and ecologically from a taxon of unknown chromosome number in the southwestern Rocky Mountains [presumably including the TX collections]. The Rocky Mountain taxon closely resembles the Mexican D. pseudofilix-mas (Fée) Rothmaler.” Mickel and Smith (2004) observed that plants from the w U.S. “may not be conspecific with those from eastern North America and elsewhere.” Thus, this widespread species (North America, Europe, Asia) is in need of detailed study and the exact nature of the TX populations is still unclear. Dryopteris filix-mas is one of the oldest known vermifuges (= a medicine that expels intestinal worms)—the drug aspidium, derived from the rhizomes, paralyzes tapeworms (which can then be expelled) but is dangerous because it also paralyzes voluntary muscles of patients, and overdoses are potentially fatal. It has been used since ancient Greek times. Livestock can also be affected upon eating the apical buds of the rhizomes—severe digestive disturbances and neurological problems including blindness can result (Correll 1956; Mabberley 1997; Yarborough & Powell 2002). Because of its rareness and extremely limited distribution in the state, we consider this species to be of conservation concern in TX.