Macromitrium microstomum Schwaegrichen 1827

Macromitrium microstomum

Macromitrium microstomum (Hook. & Grev.) Schwaegr., Sp. Musc. Suppl. 2(2):130, 1827.

Orthotrichum microstomum Hook. & Grev., Edinburg J. Sc. 1:114, 1824. [Original material: Tasmania, coll. D. Spence.]

Macromitrium saxatile Mitt., J. Linn. Soc., Bot. 12:200, 1869. [Original material: Mas a Tierra, coll. Bertero, 1830]

Macromitrium tasmanicum Broth., Oefv. Finsk. Vet. Soc. Foerh. 37:162, 1895. [Original material: South Road Forest, Circular Head, Tasmania, coll. Weymouth nos. 846, 1040, 1041.]

Macromitrium pseudo-hemitrichodes C. Müll., Hedwigia 37: 150, 1898. [Original material: North Isl., New Zealand, coll. F. M. Reader, 1882.]

Yellowish green plants with erect branches to 5 mm high. Leaves in rather evident spiral series and erect with incurved, circinate points when dry, giving branch ropelike appearance, leaves widely spreading when moist, to 1.5 mm long, 0.4 mm wide, lanceolate from a narrowly ovate base; margins plane to slightly recurved, essentially entire; apex sharply acute or more blunt with a short mucro; costa percurrent to shortly excurrent; cells of upper lamina rounded, 5–7 μm in diameter, very thick-walled, becoming longer below and toward costa; basal cells linear, ca. 50 μm long, smooth with thick walls. Autoicous. Perichaetial leaves longer and broader, slenderly long-acuminate. Setae ca. 7 mm long. Capsule urn ca. 1.5 mm long, ovate, puckered around mouth when dry. Spores 45–50 μm in diameter. Calyptra bare.

MAS A TIERRA: Cordon rechts v. Yunque, ca. 550 m, K. 309/12 (B); West Cordon Damajuana, 600 m, K. 328/17c (B); near Portezuelo de Villagra, ca. 1800 ft, H. & E. 416; trail to base of El Yunque, up to 1800 ft, H. & E. 795.

As recognized here the species occurs in Juan Fernandez, New Zealand, Tasmania, and Australia. This represents a merging of a series of species having setae mostly between 5–10 mm in length. An additional series of very closely related species with setae 1.0–2.0 cm long includes M. nitidum Hook. & Wils. of Brazil, M. owahiense C. Müll, of Hawaii, M. reinwardtii Schwaegr. of the East Indies and Pacific Islands, M. stratosum Mitt. of Central America and the West Indies, and M. weymouthii Broth. of Tasmania. Sainsbury (1955b) has discussed part of this problem, and it is possible most or all of the series will be combined ultimately under the name M. reinwardtii.