Nephrolepis exaltata

Nephrolepis exaltata (L.) Schott
(Latin: exaltatus, raised on high, lofty, in reference to the perched sites where it often grows as an epiphyte in swamps [Peck 2002])

Local names: sword fern, Boston sword fern, wild Boston fern, Yankee fern

Rhizomes short, ± erect, with wiry, widely creeping stolons; leaves monomorphic, evergreen, clustered, 1-pinnate, usually 0.4–1.5 m long, the blades linear-lanceolate, the pinnae numerous (> 18 pairs), the fertile pinnae not reduced; petiole bases with more than 3 vascular bundles; sori roundish, somewhat closer to margin than to midvein of pinnae, the sori not restricted to the uppermost pinnae, the indusia ± orbicular-reniform to horseshoe-shaped, attached at narrow or broad sinus; 2n = 82 (Mickel & Smith 2004). Escaping from cultivation; Dallas (persisting and spreading in yard in Highland Park, Dallas, R. O’Kennon, pers. obs.; Peck 2002), Hidalgo (S. Beadles 1006, BRIT), Orange (BRIT), Nacogdoches (TAES), Burnet, Henderson, Orange, and Real (Turner et al. 2003) cos.; terrestrial or more often epiphytic in its native habitat; naturalized in scattered locations in TX and in AR and LA; considered by some (e.g., Nauman 1993c, Nauman et al. 2002) to be native to FL, the West Indies, and scattered Pacific Islands; however, Weakley (2010) questioned whether the species was native to FL noting it was “rare, in our area perhaps only introduced.” Mickel and Smith (2004) give the following for distribution: “USA (Fla); Mexico; Pan; Gr Ant; Fr Gui, Braz. Native range uncertain, perhaps widely distributed in Old World tropics, but introduced there.” [Polypodium exaltatum L.] Sporulating throughout most of the year (Correll 1956). It is a commonly cultivated (particularly indoors) and commercially important fern with many cultivars including cv. ‘Bostoniensis’ (boston fern) and the locally developed dallas jewel fern,™ commonly known as the dallas fern. There is debate over the origin of the name boston fern, but it apparently originated in the late 1800s or early 1900s when plants of a particular form of N. exaltata became popular in nurseries in and around Boston, MA (Benedict 1916). Bailey (1924) noted it was “Introduced 1895.” Klingaman (2011) suggested, “Boston fern originated in a shipment of 200 plants sent from a Philadelphia florist to F. C. Becker, a florist in Cambridge, Mass….Becker recognized one plant in the shipment was faster growing, had wider fronds and an unusual drooping habit, instead of the stiffly upright form of the species. He began to propagate it in 1894. Two years later, botanists in London identified the plant and suggested the Boston name for the variant form.”

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