Macromitrium pilosum Thér.

Thouvenot, Louis, 2019, A review of the genus Macromitrium Brid. (Orthotrichaceae, Bryophyta) in New Caledonia, Cryptogamie, Bryologie 20 (16), pp. 167-217 : 197-200

Macromitrium pilosum Thér.

( Figs 1H , 16 )

Bulletin de l’Académie internationale de Géographie botanique 17:

308 (1907)

Macromitrium pilosum var. brevifolium Thér. , Bulletin de l’Académie internationale de Géographie botanique 20: 99 (1910). — Type: New Caledonia, “pied des Koghis, forêt, 300 m ”, Franc s.n. (lecto-, designated here PC[PC0083718]!) syn. nov.

Macromitrium koghiense Thér., Diagn. Esp. Var. Nouv. Mouss. 8: 4 (1910). — Type: New Caledonia, «Mts Koghis, troncs d’arbre, alt. 500 m », Franc s.n. (lecto-, designated here PC[PC0096519]!) syn. nov.

Macromitrium koghiense var. spiricaule Broth. & Paris, Öfversigt af Finska Vetenskaps-Societetens Förhandlingar 53A(11): 16 (1911). — Type: New Caledonia, Me Areimbo, L. Le Rat s.n. (lecto-, not seen; iso-, PC[PC0096520]!) syn. nov.

Macromitrium subsessile Broth. & Paris, Öfversigt af Finska Vetenskaps-Societetens Förhandlingar 51 A: 17 (1909). — Type: New Caledonia, “Mt Dzumac, ad corticem arborum”, A. Le Rat s.n. (lecto-, designated here REN[REN000099] [Herbarium E.G.

Paris]!; isolecto-, H[H-BR2561004]! [fide Isoviita in Sched. 1983], PC[PC0137890]!) syn. nov.

TYPE.— New Caledonia. “environs de Nouméa”, 1906, Franc s.n. (lecto-, designated here Herbarium Thériot s.n. PC [ PC 0096514]!)

DISTRIBUTION IN NEW CALEDONIA. — M. pilosum was hitherto only found in South Province.

TOTAL RANGE. — Endemic to New Caledonia.

SELECTED SPECIMENS. — New Caledonia. Province Sud, Koghis, 1909, Franc s.n., PC0721081 (PC); Thio, Mt Ningua, 1100 m, 29.IX.2012, Larraín 35510; Yaté, Plaine des Lacs, 245 m, 6.X.2016, Thouvenot NC2389 (PC); Dumbéa, Trail to Dzumac massif, 900 m, 26.IX.2012, Larraín 35355; Yaté, Rivière Bleue Natural Park, 216 m, 22.IX.2016, Thouvenot NC2243 (PC); Yaté, route à horaire, 105 m, 11.IX.2016, Guilloud NC 2295; Farino, Grandes Fougères Natural Park, 540 m, 22.IX.2016, Thouvenot NC2343; La Foa, Dogny plateau, 926 m, 26.IX.2016, Thouvenot NC2357 (PC); Païta, Mt Mou, 1100 m, 17.IX.2016, Thouvenot NC2310 (PC); Dumbéa, Mt Bouo, 930 m, 16.IX.2016, Thouvenot NC2300.

DESCRIPTION

Sexual

Condition unknown.

Plant

Medium, upper parts light green, lower parts olive green to light brown, creeping stems densely branched.

Branches

Thin, small to medium, 2-8(-12) mm long, 0.5-1 mm wide, straight to slightly curved, simple or furcate, when dry funiculate, with leaves erect to appressed, usually spirally arranged, carinate, the apex adaxially incurved and hidden between the neighbouring leaves, sometimes twisted on branch tips, when moist spreading recurved.

Branch leaves

Small to medium, 0.75-1.2(-1.6) mm long, 0.3-0.4 mm wide, usually lanceolate in outline, laminae lanceolate to ligulate from a wider basal part, the apices acute to obtuse and apiculate or mucronate, upper parts obscure to translucent, transitional parts short to long, basal parts undifferentiated to very short, (1/5-)1/8-1/10 the whole leaf length, costae thick, ending in apices or apiculi, margins papillose crenulate, plane.

Upper cells

Single-layered, rounded to oval, small, 6-10(-12) µm wide, thin walled, bulging, with 3-5 small papillae per cell, the cells roughly aligned, marginal cells undifferentiated or smaller in one row, usually oblate, transitional cells oval to short rectangular, walls unevenly thickened, with single rounded papillae, lower cells few, rectangular, 12-35 µm long, 7-8(-10) µm wide, thick walled, lumina wide or narrow in the same leaf, basal cells with single rounded papillae abundant to scarce but present on most of the leaves.

Perichaetia

Inconspicuous, perichaetial leaves similar to the vegetative.

Calyptrae

With dense and erect hairs.

Setae

Very short, 1-1.5(-2) mm long, erect, vaginulae with long hairs reaching the capsule.

Capsules

Short exserted, 1(-1.2) mm long, ovoid to elliptic, smooth, rim plicate, brown, small, incurved.

Peristome

Single.

Spores

Anisomorphic 20-45 µm.

REMARKS

For differences with close species, see above paragraphs dealing with Francii group and Macromitrium francii . Amongst the new synonyms, M. koghiense does not show any difference with M. pilosum , M. koghiense var. spiricaule is a form with relatively long thin branches, up to 12 mm long. The pocket of the specimen at PC was first labelled “ M. spiricaule B. P. n. sp.” handwritten by Brotherus who sent it to Thériot, the latter added the name “ M. koghiense Thér. ined.” Likely, Brotherus tooks acompte of that in his publication. Therefore, the specimen PC could be selected as a lectotype, but it would be better to look for a more pertinent sample at H.BR. A part of the type of M. subsessile , sent by Brotherus, was annotated by Thériot as similar to M. pilosum . Indeed, our observation of type specimens as well as the Brotherus protolog support the synonymy with M. pilosum . The specimen kept in H-BR as a type (unpublished) lack sporophyte whereas Brotherus protolog includes its description. We therefore chose the fertile duplicate in Paris herbarium (REN) as the lectotype. The variety brevifolium of M. pilosum , only distinguished by short leaves, cannot be retained.

Macromitrium pilosum is frequent in ultramafic as well as sedimentary massifs, on barks and twigs one meter up above the ground, from lowland up to 1200 m in scrublands or riparian, wet and cloud forests. It is significantly more present at lowest altitude, 100- 200 m.

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. 16. — Macromitrium pilosum Thér.: A, upper part of dry branch with sporophyte; B-F, branch leaves; G, transverse section in upper third of branch leaf; H, transverse section in mid-leaf; I, transverse section in apex; J, basal and marginal cells; K, upper cells in surface view; L, upper and marginal cells; M, calyptra; N, transitional and marginal cells. Drawn from the lectotype (A, C, J-N), from the lectotype of M. subsessile Broth. & Paris (D-F), from the specimen Guilloud NC2295 (B, G-I). Scale bars: A, M, 1 mm; B-F, 1 mm; G-I, 20 µm; J-L, N, 10 µm.