Adiantum amplum C.Presl

  • Authority

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

  • Family

    Pteridaceae

  • Scientific Name

    Adiantum amplum C.Presl

  • Description

    Species Description - Rhizomes short-creeping, stout, 3–5 mm diam.; rhizome scales concolorous, bright golden brown, 6–10 x 0.8–1 mm, margins ciliate-denticulate; fronds clumped, 45–80(–130) cm long, arching; stipes atropurpureous, lustrous, 20–70 x 3–5 mm, 1/3–1/2 the frond length, glabrous except at bases, or with minute tubercles or raised areas; blades broadly ovate, 3–4-pinnate proximally; rachises atropurpureous, glabrous; pinnae 4–12 compound pairs, 15–35 x 10–20 cm, alternate, long-stalked; pinnulets mostly rhombic or obovate-flabellate, 7–15(–20) x 1–2.5 mm, bases broadly cuneate, sterile margins incised-lobate and denticulate, stalked 2–6 mm, color of stalks stopping abruptly at bases of pinnulets, articulate; veins free, forking, ending in minute teeth; indument absent on both sides of blades; idioblasts absent; sori to ca. 10 per pinnulet, confined to acroscopic and distal margins, with a little yellowish farina among sporangia; indusia 1–3 mm long, oblong to lunate, glabrous.

  • Discussion

    Type. Mexico [“Mexico et in Guayaquil”]. Haenke s.n. (NY! frag. ex PR). Figs. 7A–C. Adiantum princeps T. Moore, Gard. Chron. II, 4: 197, f. 43-44. 1875. Type. Described from cultivated material originally received from Colombia, Hort Veitch, 1875, no. 16, Thomas Moore’s Fern Herbarium (K!; isotype K!). The rhomboid pinnulets and long, concolorous rhizome scales distinguish this taxon from the somewhat similar articulate species, A. tenerum. Adiantum amplum and A. tenerum seldom, if ever, grow together, the former occurring primarily on Pacific slopes, the latter on Atlantic slopes.

  • Distribution

    Terrestrial in moist forests, often along streams, roadbanks and woods, tropical deciduous forests, mostly in Pacific lowlands; 50-1500 m. Mexico; Guat, Hond, Salv, Nic, CR, Pan; Col, Ven.

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