Meteorium flexicaule Wils.

Delgadillo-Moya, Claudio, 2020, Two disjunct moss species new to Mexico, Cryptogamie, Bryologie 20 (7), pp. 83-87 : 84

Meteorium flexicaule Wils. in Hook.

Flora Novae-Zelandiae 2: 101 (1854).

SPECIMEN EXAMINED. — Mexico. San Luis Potosí, 3 km W of Ahuacatlán, c. 21°18’N, 99°04’W, 22.V.1978, in a second growth cloud forest on sunny dry Liquidambar tree trunk, Delgadillo 3766 (MEXU, MO).

DISTRIBUTION. — Meteorium flexicaule , also known as Papillaria flexicaulis (Wilson) A. Jaeger , is known from Asia, Australia, and New Zealand ( Noguchi 1976; Norris & Koponen 1985; Streimann 1988); in South America it has been reported from Brazil and Chile ( Forzza et al. 2010; Robinson 1975; Streimann 1992).

REMARKS

Meteorium flexicaule is herewith reported from Mexico for the first time. The pendent growth form with slender pinnate stems without central strand, and papillae along the walls, at least in some leaf areas, suggested a species of Cryptopapillaria M. Menzel. However , the entire leaf margins, rhomboidal cells near the leaf apex, and papillae present over cell lumens and walls, do not seem to fit that generic concept. The leaf margin in M. flexicaule has been described as plane, entire to crenulate ( Norris & Koponen 1985) while Robinson (1975) indicates that it is plane, minutely crenulate below, entire distally, and Streimann (1988) points out that the leaf margin is never denticulate.

The Mexican material contains slender, irregularly and loosely pinnate stems with short pointed branches ( Fig. 1A ), a central strand is absent but in section it shows several outer layers of thick-walled cells. Stem and branch leaves ( Fig. 1B ) are appressed ( Fig. 2A ); the secondary stem leaves lanceolate from a broad cordate base, 1.2-1.5 mm long with an attenuate apex and the margin entire; costa strong, smooth, reaching ⅔ of the leaf length or slightly longer. Branch leaves are similar, but smaller, 0.8-0.9 mm long. Distal and mid-leaf cells are rhomboidal ( Figs 1C ; 2B, C ), slightly longer in the apex, obscure, papillose on lumens and on longitudinal cell walls ( Fig. 2 B-D); the proximal cells and mid-basal cells are long, smooth or seriate papillose along the longitudinal walls or over lumens ( Fig. 2E, F ); cells at leaf base toward margins are oblate ( Fig. 1D ).

Figures

FIG. 1. — Meteorium flexicaule Wils. in Hook.: A, three-centimeter fragment of a stem. Branches are short and pointed; B, stem leaves, asterisks mark position of cells in figures C and D; C, subapical and mid-leaf cells; D, basal leaf cells. No papillae positions are shown. Scale bars: 0,1 mm.

FIG. 2. — Meteorium flexicaule Wils. in Hook.: A, tip of branch showing leaf orientation; B, leaf apex showing rhomboidal papillose cells in adaxial position; C, abaxial view showing upper leaf cells distinctly papillose while others seem party worn off;D, mid-leaf cells; E, basal leaf cells with central row of papillae over lumen; F, mid-leaf basal cells, lowermost cells with papillae in two rows. Scale bars: A, 500 µm; B, 50 µm; C, 40 µm; D, E, 10 µm; F, 20 µm.