Pterozonium brevifrons (A.C.Sm.) Lellinger

  • Authority

    Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.

  • Family

    Pteridaceae

  • Scientific Name

    Pterozonium brevifrons (A.C.Sm.) Lellinger

  • Description

    Species Description - Rhizomes short-creeping or ascending, up to ca 10 cm long, 5-8 mm thick, the scales spreading, brown to blackish, bristle-tipped, abundant over the entire rhizome; fronds simple, up to ca 50 cm long, clustered near the rhizome apices; stipes (4-) 7-25 (-28) cm long, 1-1.5 mm diam, (1.5-)2-3(-4) times longer than the blades, adaxially flattened or slightly grooved with short, sometimes stramineous wings prominent distally, otherwise atropurpureous throughout; midribs abaxially keeled; laminae ovate or long ovate, 4-13.5 cm long, 2 -4.5 cm wide, ca 1.8-3 times longer than wide, the longer blades relatively narrower, rounded apically, deeply to shallowly cordate basally (the juveniles triangular-ovate with cuneate bases); veins 0.5-1 mm distant, hydathodes elongate, submarginal (absent in juveniles); margins entire, slightly inrolled at maturity; sori in a central band extending outward from near the midrib toward and rarely almost to the margins; paraphyses few-celled, hyaline, the apical cell spherical and glandular, the wax yellow, orange, reddish, or aljsent.

  • Discussion

    Syngramma brevifrons A, C. Sniitli, Bull. Torrey Club 57: 17S. 1930. Type. Mount Roraima, summit, Bolivar, Venezuela, Tate 4:21 (NY, fragment US).

    Syngrammalopsis brerifmyis (A. C. Smith) Alston, Mutisia 7: 8. 1952. Sj/ngramma versicolor Vareschi, Acta Bot. Venez. 1(2): 90, fJf- 1966. Type: Chimantatepui, Bolivar, "Wnczucla, Steyermark 75609 (VEN not seen, isotypes NY, US)

    Pterozonium brevifrons has lighter colored hydathodes and the veins of its laminae are less conspicuous than those of P. paraphysatum. Specimens with inconspicuous hydathodes can be distinguished from P terrestre by their laminae which on the whole are more ovate and less linear or quadrangular. In addition! their sti]x^s aic generally 2-3 times longer than the laminae, not 1-1.5 times longer, as are those of P terrestre. The smallest specimens {Sfcjiermark 75609) are triangular-ovate, with rounded apices and truncate to cuneate bases. Their midribs are scarcely if at all keeled, their margins are somewhat crenate, lack obvious hydathodes. Although they do not seem offhand to belong to this species, Steyermark 94065 (US) includes both juvenile fronds of this type along with a series tending toward fully mature, typical fronds. The type specimen consists wholly of rather juvenile fronds. The juveniles also superficially resemble some juveniles of P. scopulinum. In P scopulinum, hydathodes are present and the lamina bases are always cordate.

    Distribution and Ecology: In dry rock crevices both in the eastern and central portions of the Guayana Highland, including the Sierra de la Macarena, and in Amazonian Peru about 450 miles southwest of the Guayana Highland. PERU . Amazonas: 3-6 k m west of Molinopampa, alt 2200-2450 m, Wurdack 1408 (US), 1409 (US). COLOMBIA . Meta: Sierra de la Macerena, northern escarpment, Philipson 2322 ( B M photograph 7483 US). VENEZUELA . Amazonas: Cerro Huachamacari, upper escarpment, Maguire, Cowan d' Wurdack 29799 (NY, U S ) ; Cerro de la Nel)Una, on escarpment slopes E of Camp 3, alt 1600 m, Maguire, Wurdack d' Bunting 37374 (US) ; Bolivar: Cerro Venamo, southeast part, just below summit, alt 1400-1575 m, Steyertnark d- Diinsterville 92549 (US); Auyan-tepui, at the peak of the upper escarpment, alt 2100 m, Steyertnark 94065 (US); Chimanta Massif, Chimanta-tepui (Torono-tepui), western slopes, along trail from base camp to Bluff Camp, alt 110-1700 m, Slciiermark 75609 (NY, US) 75610 (NY US).

  • Distribution

    Peru South America| Amazonas Brazil South America| Colombia South America| Venezuela South America|