Nephrolepis hirsutula (G.Forst.) C.Presl

  • Authority

    Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.

  • Family

    Nephrolepidaceae

  • Scientific Name

    Nephrolepis hirsutula (G.Forst.) C.Presl

  • Description

    Species Description - Rhizomes erect, well developed, stolons stout, lacking tubers; rhizome scales bicolorous, 2–3 x 0.8–1 mm, dark reddish brown to blackish, lustrous, central portion sclerotic, margins whitish fimbriate-ciliate, appressed; stipes 5–25 cm long, ca. 1/5 the frond length, stramineous to light brown, with moderate to dense, lanceolate, appressed, bicolorous scales with dark sclerotic center and narrow, membranous, sometimes fibrillose margins; blades linear-elliptic, 30–70 x 6–15 cm; rachises with dense, appressed, white, fibrillose scales; pinnae narrowly deltate, obtuse to acute, bases slightly unequal, acroscopic auricle narrow, acute, basiscopic side rounded to short-auriculate; indument abaxially, especially on costae, of whitish fibrillose scales, adaxially the costae with dense hairs 0.1–0.3 mm long and scattered fibrillose scales; hydathodes sometimes lime-dotted on adaxial blade surfaces; indusia dark reddish brown or pale with dark center, roundreniform, 0.8–1 mm diam., each with a narrow sinus (mature sporangia projecting on all sides); 2n = 82 (India).

  • Discussion

    Polypodium hirsutulum G. Forst., Fl. Ins. Austr. 81. 1786. Type. Probably Polynesia, Society Islands, Tahiti, Forster s.n. (holotype or isotype BM, Morton photo 6876). For discussion and comments, see Morton, Contr. U.S. Natl. Herb. 38: 345. 1974. Davallia multiflora Roxb., Calcutta J. Nat. Hist. 4: 515, t. 31 [left]. 1844. Nephrolepis multiflora (Roxb.) Jarrett ex C. V. Morton, Contr. U.S. Natl. Herb. 38: 309. 1974. Lectotype (chosen by Morton, Contr. U.S. Natl. Herb. 38: 309. 1974). India. Roxburgh s.n. (BR!, frag. and photo US!).

    This is a fairly recent introduction to the New World and is rapidly becoming naturalized in many countries. About 35 collections have now been seen from Mexico, especially from eastern Chiapas and southern Veracruz, and nearly all have been collected since 1970. In the Greater Antilles, N. hirsutula is now one of the dominant species on roadbanks. Although often misidentified as N. exaltata or N. biserrata, the dense adaxial hairs on the costae, bicolorous (black-centered) appressed rhizome and stipe scales with fimbriate margins, lack of septate hairs on the blades abaxially and adaxially, and narrow whitish scales on the costae abaxially distinguish this taxon. In floristic accounts for New World areas, N. multiflora is usually the name applied to this species, but Bell (in McCarthy, 1998: 444), citing Du Puy in Fl. Australia 50: 568, 1993, noted the almost certain conspecificity of N. multiflora with the widespread N. hirsutula. R. Tryon and Stolze (1993: 52) distinguished these species in Peru by N. hirsutula having the costae adaxially “moderately to densely invested with dissected scales, rather than pubescent as in N. multiflora,” but we find dissected scales on all specimens so identified as N. multiflora, in both the Neotropics and Paleotropics. Thus, we are unable to distinguish these two species in herbarium holdings, and so apply the oldest name. A cultivar of this species, N. hirsutula ‘Superba’, is occasionally grown, e.g., in the sitios of San Cristo´bal las Casas (Chiapas): Breedlove 16031, DS