Athyrium filix-femina
Athyrium filix-femina (L.) Roth subsp. asplenioides (Michx.) Hulten
(sp.: Latin: filix, fern and femina, femaleor woman, = lady fern, in reference to the more delicate or graceful appearance of this species in comparison with the superficially similar Dryopteris filix-mas, male fern; subsp.: resembling Asplenium—spleenwort, and Greek: -eides, -oides, like, in reference to the elongate Asplenium-like sori)
Local names: southern lady fern, lowlandlady fern, spring fern
Plant terrestrial; rhizomes short-creeping; leaves monomorphic, deciduous, clustered, typically (30–)60–120 cm tall; leaf blades 2-pinnate-pinnatifid (rarely sub-3-pinnate), usually widest near base (only basal 1 or 2 pairs of pinnae shorter), the pinnae usually short-stalked, the ultimate segments (= smallest subdivisions of leaf) with veins free, simple or forked, marginally serrate; petioles greenish or strawcolored, often red- or brown-tinged, with light brown to brown scales (these often early deciduous), the petiole bases swollen (functioning as trophopods), dark reddish brown or blackish, persistent, with 2 vascular bundles; sori elongate along veins, straight to hooked or curved, somewhat resembling those of Asplenium, in a single row on each side of the midvein, ca. midway between midvein and margin of ultimate leaf segments; indusia membranous, with elongate attachment along one side, the attachment as long as the elongate sori, opening facing midvein; spores brown to dark brown; 2n = 80 (Kato 1993a). Moist woods, thickets, swamps, stream banks; Pineywoods (e.g., Bowie Co., E. Whitehouse 20364, BRIT), n Gulf Prairies and Marshes, and w Post Oak Savannah (Leon Co., Turner et al. 2003) and disjunct w to Williamson Co. (Correll 1956 cited E.N. Plank s.n.; Turner et al. 2003) in the Blackland Prairie; e U.S. from NY s to FL w to KS and TX. Sporulating May–Nov. [A. asplenioides (Michx.) A.A. Eaton, A. filix-femina var. asplenioides (Michx.) Farw.] Although this taxon has traditionally been treated at the varietal level (e.g., Correll 1956), we are following a number of recent authors (e.g., Yatskievych 1999; Nauman et al. 2000) in recognizing it as distinct at the subspecific level from the more northerly subsp. angustum (Willd.) R.T. Clausen. Even though hybrids are known between the two, Kelloff et al. (2002) noted “…substantial differentiation between the Athyrium taxa angustum and asplenioides and the consistent characters uniting a vast number of individuals north and south of their hybrid zone suggest that the taxa should be ranked at least at the level of subspecies. Ranking at the species level would not be inconsistent with the treatment of such taxa in the broader plant literature.” It is thus possible that the two taxa will be consistently recognized as distinct species in the future. In fact, both subspecies occur in AR, and J. Peck (pers. comm.) considers them to be distinct species. Weakley (2010) also treated them at the species level. Sciarretta et al. (2005) summed it up nicely when they said subsp. angustum and subsp. asplenioides are “very recently diverged taxa” and that the Athyrium filix-femina complex “seems to represent a lineage ‘caught in the act’ of speciating.” Subspecies angustum can be distinguished by its leaf blades usually being widest near the middle, its brown to dark brown petiole scales, and its yellow to light brown spores. This species is sometimes cultivated as an ornamental, and is said to be “one of the most dependable and often-used in fern gardening” (Nelson 2000). It is quite variable with numerous horticultural forms. The cultivars are thought to be derived from the European taxon, subsp. filix-femina (Hoshizaki & Moran 2001). The species as a whole occurs broadly across the n hemisphere and has a classic Arcto-Tertiary distribution (see page 33) (Kato 1993b).