Cyrtomium falcatum
Cyrtomium falcatum (L.f.) C. Presl
(Latin: falcatus, sickle-shaped or hooked, in reference to the curved pinnae)
Local names: Japanese net-vein holly fern, Japanese holly fern, house holly fern
Terrestrial or on rocks or masonry; rhizomes short, stout, conspicuously scaly, the scales orangish brown; leaves monomorphic, evergreen, 28–60(–100) cm long; petioles conspicuously scaly at least near base; leaf blades 1-pinnate, 15–35 cm long, leathery-thickened; pinnae short-stalked, 4–10(–12) pairs, 4–8.5(–11) cm long, 1.5–3 cm wide, obliquely ovate to lanceolate, usually falcate (= sickle-shaped), sometimes with a short basal lobe on the acroscopic side (= side toward the leaf apex) of the pinnae, apically acuminate, marginally variable ranging from nearly entire to undulate or irregularly and coarsely dentate (sometimes even appearing fringed), often nearly entire near the tips, bright green and shiny on upper surface, the terminal pinna typically with more lobing/large teeth than laterals, the veins anastomosing and thus forming areoles which then contain free veinlets; sori round, conspicuous, scattered over whole lower (= abaxial) surface of pinnae (sometimes appearing to be in rows); indusia peltate, at first pale, then becoming brownish or even blackish in center, not shriveled at maturity; n = 2n = 123 (Yatskievych 1993a). Widely cultivated and escaped; in the Pineywoods in Houston Co. (Davy Crockett Natl. Forest—Stotts 38, HPC) on remnant brick wall of old sawmill site and in San Jacinto Co. (E. Keith 3, BRIT) “growing out of the wall of a waterfall,” also in the Post Oak Savannah on stream bank in Waller Co. (E. McWilliams 1995-100, BRIT) and on bluff in Burleson Co. (Wilson s.n., TAMU), and near w margin of Blackland Prairie in Bell (Sanchez & Pekins 4651, TEX-LL on limestone cliff), Hays (Carr 18255, TEX-LL on limestone bluff), and Travis (W.R. Carr, 6019, BRIT, on moist limestone boulders) cos.; also Jefferson (BAYLU) and Harris (BRIT, TEX-LL) cos. in n Gulf Prairies and Marshes and Tarrant Co. (Turner et al. 2003) in the Cross Timbers and Prairies; naturalized se U.S. from SC s to FL w to AR (Peck 2011a) and TX, also CA and VA (Weakley et al. 2012) and reported from CN, NJ, NY, OH, and OR (USDA PLANTS 2012). Sporulating spring–fall. Native of e Asia. [Phanerophlebia falcate (L.f.) Copel., Polypodium falcatum L.f., Polystichum falcatum (L.f.) Diels] All U.S. plants appear to be apogamous triploids (Yatskievych 1993a). Matsumoto (2003) recognized three subspecies within C. falcatum. Hoshizaki and Moran (2001) noted “In wild plants the margins are nearly entire, although a few obscure, minute teeth may be present.” This widely cultivated species is naturalized in many parts of the world (e.g., Australia, Azores, Great Britain), including various parts of the U.S. (Yatskievych 1993a; Mabberley 1997). There are a number of cultivars with one of most common being the rockford fern (cv. ‘Rochfordianum’), which has obviously fringed pinnae margins (Hoshizaki & Moran 2001). While we are not treating infraspecific taxa in this species, J.H. Peck (pers. comm.) indicates that most of the material he has seen is consistent with either subsp. falcatum as can be found in the area around Tokyo (see Oka 2008) or with the rockford fern cultivar. While in TX this species is typically found growing on rocks (often limestone) or old masonry, it is also known to be halophytic (adapted to live under high salt conditions). In its native range (e Asia) and elsewhere it is often found in maritime environments (Zhao et al. 2002, 2011; Diaz et al. 2005).