The World Flora Online

Amphidium tortuosum (Hornsch.) Cuf., Oesterr. Bot. Z. 98: 221. 1951.

Amphidium tortuosum (Hornsch.) H. Robinson, Smithsonian Contr. Bot. 27: 20. 1975, comb. redun. Syrrhopodon tortuosus Hornsch., Linnaea 15: 117. 1841. Protologue: South Africa, Cape of Good Hope, Teufelberges, 1827, Ecklon.

Zygodon cyathicarpus Mont., Ann. Sci. Nat., Bot. sér. 3, 4: 106. 1845. Amphoridium cyathicarpum (Mont.) Jaeg., Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1872–73: 108. 1874. Amphidium cyathicarpum (Mont.) Broth., Nat. Pflanzenfam. 1(3): 460. 1902. Protologue: Chile, San Antonio, 1829, Gay.

Plants to 3 cm high, irregularly and sparingly branched. Leaves crisped dry, flexuose‑erect when wet, to 3(–4) mm long, keeled, linear‑lanceolate to linear; apices sharply acute, often fragile; margin plane and remotely notched‑serrulate above, recurved below; costae subpercurrent; upper cells 6–12 μm, rounded‑quadrate to shortly rectangular, lower cells short‑oblong to rectangular, 20–36 μm, with multiple papillae arranged in longitudinal rows and appearing papillose‑striolate. Autoicous, perigonia just below perichaetia or paroicous. Setae 2–5 mm long, curved to flexuose, occasionally erect. Capsules urceolate, to 1 mm long. Spores 14–16 μm, finely papillose.

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The plants are recognized by their crisped, linear-lanceolate to linear leaves with irregularly serrate margins and striolate-papillose cells, scarcely differentiated perichaetial leaves and immersed capsules.

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Plants small, yellow-green to green above, yellow-brown to brown below; saxicolous to terricolous. Stems up to 28 mm tall, branching by subperichaetial innovations, scarcely tomentose below; rhizoids red or reddish brown, smooth to papillose; in section subround to subtriangular, inner cortex 4-8 cells across, thin-walled, outer cortical cells smaller, in 1 or 2 rows, rarely absent on one side, incrassate, minutely papillose. Leaves crowded, ± equal in size, erect and crisped when dry, erect-spreading and flexuose when wet; linear-lanceolate to linear, 2.0-4.8 mm long; apex acute to acuminate, with a single apical tooth; margins plane, frequently recurved on one side below, irregularly serrate, frequently denticulate at shoulders, rarely decurrent. Costa ending below apex; ventral and dorsal superficial cells narrowly rectangular; in section crescent-shaped to subround, bulging dorsally, ventrally flat, laminal insertion ventral, guide cells in one layer medially, ventral substereid or stereids in one layer, papillose, dorsal stereids in 1 or 2 rows, surface rough. Upper laminal cells rounded-quadrate or oval, incrassate, bulging ventrally, papillose, striolate, 6-14 µm, papillae low, blunt, scattered over dorsal and ventral surface; basal cells rectangular, thin-walled, smooth to striolate. Autoicous. Perigonia terminal on short, subperichaetial branches; inner leaves ovate to ovate-apiculate to ovate-acuminate, margins irregularly crenulate. Perichaetia terminal, frequently overgrown by subperichaetial innovations; leaves scarcely differentiated, linear-lanceolate, 2.5-3.8 mm long, sheathing below, base oblong or oval. Seta 0.9-1.5 mm long, frequently curved, yellowish. Capsule erect to inclined, immersed, urceolate, brownish, urn 0.3-0.5 mm long, neck 0.2-0.3 mm long; exothecial cells irregularly rhomboidal to rectangular, ± thin-walled, in 2 or 3 transverse rows at mouth, smaller at mouth; stomata present on neck. Operculum conic-apiculate, oblique. Calyptra 0.5-0.6 mm long, cells smooth to papillose. Spores 12-22 µm.

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In rock crevices.

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Primarily a southern hemisphere species, Amphidium tortuosum is known from Mexico, South America, Juan Fernandez islands, South Georgia, Hawaii, Australasia, Indonesia and sub-Saharan Africa. In southern Africa the species is rarely collected from rock crevices on the mountains of KwaZulu-Natal and Lesotho and on Table Mountain in the southwestern Cape region.

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