Adiantum melanoleucum Willd.

  • Authority

    Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.

  • Family

    Pteridaceae

  • Scientific Name

    Adiantum melanoleucum Willd.

  • Description

    Deprecated: mb_convert_encoding(): Handling HTML entities via mbstring is deprecated; use htmlspecialchars, htmlentities, or mb_encode_numericentity/mb_decode_numericentity instead in /home/emu/nybgweb/www-dev/htdocs/science-dev/wp-content/themes/nybgscience/lib/VHMonographsDetails.php on line 179

    Species Description - Rhizome creeping, 2-7 mm thick (excluding scales and stipe bases), clothed toward apex with dark or blackish-brown, iridescent, clathrate, linear- attenuate scales 2-5 mm long, the tips hairlike. Fronds very closely crowded-distichous, spreading to suberect, mostly 20-65 cm long; stipes lustrous purple-black, 6-32 cm long, 0.2-2.5 mm in diam., shorter to longer than the blade, grooved adaxially, glabrous but minutely scabrous. Blades highly variable, linear and 1-pinnate in small forms (these sometimes fertile), but in ordinary mature plants deltate-ovate or broadly subpentagonal, 17-35 cm long, 10-26 cm broad, essentially 2-pinnate (but usually 3-pinnate at base by presence of an elongate basiscopic pinnate pinnule at base of each basal pinna); rhachis glabrous or minutely pubemlous on abaxial side; pinnae 2-8 pairs and a similar or larger terminal one, oblique, distant, mostly linear-attenuate; pinnules dimidiate, oblong or obliquely deltate-oblong, rounded-obtuse or truncate at apex, cuneate or rectangular at base, the basiscopic side straight or concave; tissue thin-membranous, often glaucous beneath. Sori 2-6 per pinnule, mostly 1.5-3.5 mm long, oblong- lunate to linear and more or less deeply curved, occupying shallow lobes on the acroscopic margin and apex, the ends of these lobes often projecting beyond each soms; indusioid flap dark brown, turgid, glabrous, with minutely erose decurved margin.

  • Discussion

    Type. Plumier, Traite foug. Amer., t. 96, based on material collected along the Grande Riviere, near Leogane, Haiti.

    Syn, Adiantum kunzeanum Klotzsch, Linnaea 18: 555, 1844, not K. Presl, 1836. (Type. Poeppig s.n., from Cuba, LZ, destroyed.)

    Adiantum cubense Hooker, Sp. fil. 2: 8, t. 73A. 1851. (Type. Linden 1867, from Oriente, Cuba, K, isotype L.)

    Adiantum cubense var. nanum Jenman, J. Bot. 17: 258, 1879. (Type. Jenman 75 in 1878, from Jamaica, K.)

    Adiantum melanoleucum var. nanum (Jenman) Jenman, Bull. Bot. Dept. Jamaica no. 35: 6. 1892.

    General Distribution. Florida, Bahamas, Greater Antilles, and Cayman Islands. Distribution in Puerto Rico. Confined to the north side of the island west of San Juan; recorded from Arecibo, Camuy, Ciales, Florida, Isabela, Quebradillas, San Sebastian, Utuado, Vega Alta, and Vega Baja. Habitat. Shaded stony banks and crevices of limestone boulders and cliflfs at low to middle elevations (10-360 m), locally common. It is sometimes difficult to distinguish this species from the next; in such cases, the color, shape, and cell stmcture ofthe rhizome scales is often helpful.

  • Distribution

    Florida United States of America North America| Bahamas South America| Cayman Islands South America| Vega Baja Puerto Rico South America| Vega Alta Puerto Rico South America| San Sebastián Costa Rica Central America| Utuado Puerto Rico South America| Vega Alta Puerto Rico South America| Vega Baja Puerto Rico South America|