Zygodon Hooker & Taylor, Musc. Brit. 70. 1818.
[yoked (or paired teeth), referring to the 16 peristome teeth that initially are joined in pairs in some of the species]
Dale H. Vitt
Plants to 10 cm. Stem leaves loosely-erect and irregularly twisted or curved around stem, sometimes undulate when dry, erect-spreading to squarrose-recurved when moist, oblong-lanceolate to linear-lanceolate, 0.5--2.0 mm, acute, usually apiculate, keeled, decurrent; margins entire or ± denticulate near apex; costa percurrent, ending near apex, or rarely excurrent; distal laminal cells 4--14 µm wide, densely pluripapillose, smooth or with 3--6 small, clavate papillae per cell, somewhat to very thick-walled; basal laminal cells usually yellowish, subquadrate to rectangular; gemmae elliptic to cylindric or fusiform, 4 to many celled, axillary. Sexual condition dioicous, autoicous, or synoicous, rarely with sporophytes. Seta 3--13 mm. Capsule elliptic-oblong to fusiform, 1--2 mm, strongly 8-ribbed along ± the entire length, not constricted beneath mouth; peristome double, single, or lacking; endostome segments 8 or 16, when present; exostome teeth 8 or 16 partially united into 8 pairs. Spores 11--22 µm.
Species ca. 90 (5 species in the flora): North and South America; Europe; Asia, Africa, Australia, Pacific Islands (New Zealand).
Sporophytes are rarely produced in many species of Zygodon, and taxa are delimited on characters derived exclusively from the gametophyte. Largely pan-tropical with several widespread temperate species. None of the species is found farther north than 60° N latitude.
