Zygodon Moss

Zygodon viridissimus (Dicks.) Brid. Bryol. Univ. 1: 592. 1826
Bryum viridissimum Dicks. PI. Crypt. Brit. 4:9. 1801. Dicranum viridissimum Smith, Fl. Brit. 1224. 1804. Gymnostomum viridissimum Smith, Engl. Bot. pi. 1583. 1806. Amphoridium viridissimum De-Not. Atti Univ. Genova 1: 277. 1869.
Plants in small, bright green tufts or cushions 1-2 cm. high; stems erect or ascending, tomentose with more or less papillose radicles, which often bear 4or 5 -celled, clavate broodbodies; leaves close, somewhat twisted and contorted when dry, spreading and recurved when moist, 1-2 mm. long, linear-lanceolate to oblong-lanceolate, acuminate and often subulate at the apex and ending in 1 or 2 single elongate cells, carinate, the margins plane and entire; costa vanishing below the apex; upper median leaf-cells rounded, thick-walled, papillose on both sides, 8-1 1m in diameter; basal cells short-rectangular, rounded at the angles, incrassate, smooth; small, clavate, jointed brood-bodies of 3-5 cells often found on the leaves and in the axilsinner perichaetial leaves smaller, their basal cells nearly linear; dioicous; seta 3-7 mm. long, terminal, becoming lateral by innovations; capsules elongate-pyriform, 1.5-2 mm. long, 8-ribbed when dry and empty, contracted at the mouth; calyptra fugacious; operculum obliquely rostrate; annulus and peristome lacking; spores rough, 13-16 p. in diameter, maturing in summer.
Type locality: England.
Distribution: Mostly on trees; Hudson Bay; northern New York, south to Georgia; Washington; Arizona; Europe; Macronesia; North Africa; Asia Minor; the Caucasus.