1. Cratoneuron (Sullivant) Spruce, Cat. Musc. 21. 1867. • [Greek cratos, strong, and neuron, nerve, alluding to leaf costa].
Hypnum sect. Cratoneuron Sullivant in A. Gray, Manual ed. 2, 673. 1856
Plants medium-sized, green, yellowish, or rarely brownish. Stems pinnate or irregularly branched; hyalodermis absent, central strand present; paraphyllia few to many, rarely absent, ; rhizoids or rhizoid initials on stem or abaxial costa insertion, often forming tomentum, usually strongly branched, smooth; axillary hair distal cells 1 or 2, hyaline. Stem leaves not recurved or squarrose, straight or falcate, narrowly to broadly triangular or rounded-triangular, sometimes ovate, not plicate, longer than 1 mm; base decurrent; margins plane or near base slightly recurved, denticulate or serrulate almost throughout, limbidia absent; apex acuminate, ; costa strong, single, usually percurrent or excurrent, sometimes ending well before apex; alar cells differentiated, strongly inflated, hyaline, region well defined, transversely triangular; medial laminal cells elongate-hexagonal, short-rectangular, rectangular, short-linear, or rarely linear, ; marginal cells 1-stratose. Sexual condition dioicous. Capsule horizontal, cylindric, curved; peristome perfect; exostome margins slightly dentate distally; endostome cilia 2 or 3, well developed, nodose. Spores 14-21(-25) µm.
Species 2 (1 in the flora): North America, South America, Eurasia, Africa, Atlantic Islands, Pacific Islands (New Zealand).
Cratoneuron grows in slightly or strongly calcareous habitats that are at least periodically wet; plants have a strong leaf costa, relatively short, smooth laminal cells, and mostly lanceolate and leaflike paraphyllia. The differences between Cratoneuron and 2. Palustriella are described under the latter.