Plants: to 2.3 cm. Stem: leaves loosely erect and ± spirally twisted to somewhat contorted, sometimes falcate-secund at stem apices when dry, erect-spreading to spreading when moist, lanceolate, narrowly so, elongate-lanceolate, oblong-lanceolate, or linear-lanceolate, 1–2 mm; margins entire or irregularly serrulate or serrate near apex, somewhat wavy; apex acute with gradual apiculus, apiculate, short-apiculate, or short-acuminate; costa ending below apex, abaxial surface covered by quadrate papillose cells distally; basal laminal cells subquadrate to rectangular; distal cells 7–11 µm, papillae 2–4 per cell, walls somewhat thick. : Specialized asexual reproduction by clavate, elliptic, or subcylindric gemmae, longitudinal walls present or absent. Sexual: condition dioicous. Sporophytes: unknown. North America, Mexico, Central America, Europe, w Asia, Africa, Atlantic Islands (Canary Islands).
Varieties 5 (3 in the flora). Zygodon viridissimus in the flora area includes phenotypes with ovate to elliptic gemmae; narrowly lanceolate, loosely erect leaves; the abaxial surface of the distal 1/3–1/2 of the costa covered with papillose, quadrate cells; dioicous sexual condition; and rudimentary (or no) peristome.
Plants: to 1.5 cm, light green to olive green. Stem: leaves oblong-lanceolate to lanceolate; margins entire; apex short-apiculate. : Specialized asexual reproduction by ovoid to elliptic gemmae, of 5–10 cells, longitudinal septa present, ± straight.
Trunks of trees, conglomerate boulders. low elevations. N.S., Que., Europe.
Variety viridissimus is distinguished by the entire leaf margins and gemmae with longitudinal septae.