Macromitrium cardotii Thér.

Thouvenot, Louis, 2019, A review of the genus Macromitrium Brid. (Orthotrichaceae, Bryophyta) in New Caledonia, Cryptogamie, Bryologie 20 (16), pp. 167-217 : 180-182

Macromitrium cardotii Thér.

( Figs 1B , 6 )

Diagnoses d’Espèces et de Variétés nouvelles de Mousses 8ème article:

5 (1910).

TYPE. — New Caledonia. Tao, forêt, sur les écorces, alt. 600 à 800 m, 1910, Franc s.n. (lecto-, designated here PC [ PC 0096512]!; isolecto-, PC [ PC 0137618]!).

DISTRIBUTION IN NEW CALEDONIA. — An infrequent species, corticolous in cloud forests and shrublands in the highest parts of the mountains, frequently foggy.

TOTAL RANGE. — Endemic to New Caledonia.

SELECTED SPECIMENS. — New Caledonia. Province Nord, Hienghène, Mont Panié, 18.IX.2001, on the path from the road RPN3 to the summit, epiphyte in a very wet forest, c. 1200 m, Frank Müller NC128 (DR); Hienghène, summit of Mont Panié, 09.X.2012, epiphyte in open shrub vegetation and forest with Agathis montana and Araucaria schmidii , 1640 m, Larraín 35875. Province sud, Dumbéa, Montagne des Sources, 21.IX.2016, on bark in mountain wet forest with Araucaria rulei , 950 m, Thouvenot NC2331.

DESCRIPTION

Dioicous (?).

Plant

Medium sized, upper parts yellow-green often red tinged, older lower parts red-brown, creeping stems loosely branched.

Branches

Medium to long, 8-20 mm long, 2 mm wide, slightly curved, simple or sometimes furcate, when dry curly with dense leaves loosely erect, individually twisted, carinate, the apex incurved to circinate or cork-screw like, when moist erect to patent, the apex little incurved to straight.

Branch leaves

Large, 3-4.5 mm long, 0.35-0.75 mm wide, narrowly lanceolate, long acuminate, widest above the base at c. 0.15 the leaf length, upper part obscure, basal part translucent, ¼-¹⁄₅ the leaf length, apex acute rarely asymmetrically truncate, mucronate to aristate, aristae up to 250 µm long, costae relatively thin, excurrent, margins papillose-crenulate, slightly recurved in one side near base.

Upper cells

Single-layered, relatively large, 10-20 µm long, 7-12 µm wide, thick walled, with rounded to oblong lumina green or red, outer walls thicker, strongly bulging, with several papillae simple or furcate, marginal cells smaller in 1-2 bands, intermediate cells short rectangular, thick walled, nodulose at angles, with single rounded papillae, lower cells elongate, rectangular to linear, 25-75 µm long, 7-12 µm wide, very thick walled, walls 3-4 µm wide, more or less porous, lumina straight, narrow, single papillae usually numerous, rounded to high conical.

Perigonium

Not seen.

Perichaetia

More or less conspicuous, loosely erect, not sheathing, perichaetial leaves similar to the vegetative, but longer aristate.

Calyptrae

Narrow, plicate, naked.

Setae

Usually large, 10-35mm long, thin, straight, vaginulae hairless but with short paraphyses.

Capsules

2 mm long, 0.5 mm wide, narrowly oblong, smooth, plicate below the small rim.

Peristomes

Present, single, caducous.

REMARKS

Macromitrium cardotii is characterized by:1) long branches red tinged to brown, usually simple; 2) large narrow leaves gradually narrowing from a short basal part to a narrowly acute apex usually short aristate, papillose thorough; 3) upper cells bulging with thicker external walls protruding, in section lens or cone like, with several small papillae; 4) long setae with oblong capsules; 5) peristomes single, caducous; and 6) naked calyptrae.

The leaf shape and the presence of a peristome distinguish it from M. pulchrum and M. neo-caledonicum which, otherwise, share comparable leaf size, seta size and cell network. The gametophytes of M. pulchrum and its varieties as well as M. rufipilum differ from M. cardotii as follow:

Macromitrium pulchrum and varieties:obtuse to shortly acute leaf apices, muticous or short aristate, and shorter branches or, if longer, leaves recurved to squarrose when moist.

Macromitrium rufipilum : longer red aristae, ligulate leaves with obtuse apices and smooth basal cells.

Sterile plants of M. leratii might be difficult to separe from M. cardotii in the absence setae, shorter in M. leratii , but the gametophytes of M. leratii may be separated from by the following characters: smooth basal cells, small upper cells, 6-8 µm long, locally two-layered, percurrent nerve.

The specimen selected as lectotype is labelled in accordance with the diagnosis and is dated on January 1910. Since the travelling time from New Caledonia to France was usually three months at that time, that is consistent with the date of publication of the new species: November 1910.

Figures

FIG. 1. — Dry branch habits of Macromitrium Brid. (I) A, M. microstomum Hook. & Grev.; B, M. cardotii Thér.; C, M. francii Thér.; D, M. laevigatumThér.; E, M. leratii Broth. & Paris.; F, M. taoense Thér.; G, M. plicatum Thér.; H, M. pilosum Thér.; I, M. pulchrum Besch. From type specimens (B, D, F-I), from specimens Thouvenot NC881 (A), NC2379 (E), from specimen Coulerie COU85 (C). Scale bars: 1 mm.

FIG. 6. — Macromitrium cardotii Thér.: A-D, branch leaves; E, branch leaf apex; F, transverse section in top quarter of branch leaf; G, upper cells;H, I, basal cells; J, upper cells in side view. Scale bars: A-D, 1 mm; E, 100 µm; F, 20 µm; G-J, 10 µm. All drawn from the lectotype.