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BFNA | Family List | BFNA Vol. 2 | Orthotrichaceae

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.

1 Distal leaf cells smooth.   Zygodon menziesii
+ Distal leaf cells papillose.   (2)
2 (1) Leaves squarrose-recurved, bluntly acute; distal leaf cells 4--9 µm, very thick-walled; gemmae never present.   Zygodon gracilis
+ Leaves spreading to ± recurved, sharply acute-apiculate; distal leaf cells 5--14 µm, moderately thick-walled; gemmae always present.   (3)
3 (2) Abaxial surface of costa covered by quadrate, papillose cells only at extreme apex; synoicous.   Zygodon reinwardtii
+ Abaxial surface of costa covered by quadrate, papillose cells in distal 1/3 to 1/2 of leaf; dioicous.   (4)
4 (3) Gemmae fusiform-cylindric, never with transverse walls; distal leaf cells 9--14 µm wide.   Zygodon conoideus
+ Gemmae clavate to ellipsoidal, with or without transverse walls; distal leaf cells 5--11 µm wide.   Zygodon viridissimus

Lower Taxa

Related Synonym(s):


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Flora of North America  
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