Plants: medium-sized, in thin to dense mats, light to yellowish or dark green, somewhat glossy to glossy. Stems: creeping to ascending or erect, simple or sparingly and irregularly branched; hyalodermis present, sometimes indistinct, central strand usually indistinct or absent; pseudoparaphyllia absent (foliose in H. adscendens). Stem: and branch leaves similar, spreading to squarrose, not undulate, ovate or lanceolate, not or weakly plicate; base decurrent or not; margins plane, serrulate to serrate (serrulate to entire in H. adscendens); apex acuminate to long-acuminate; costa double and short or rarely ecostate; alar cells usually clearly differentiated, few quadrate, rectangular, or abruptly inflated, rounded cells present; laminal cells smooth. : Specialized asexual reproduction absent. Sexual: condition autoicous or dioicous; perichaetial leaves ovate-lanceolate, apex gradually acuminate, acumen occasionally filiform. Seta: light brown to red or yellowish. Capsule: erect to inclined, oblong or cylindric, straight to arcuate, often contracted below mouth when dry; annulus 2- or 3-seriate, deciduous, cells large; operculum conic to conic-apiculate; peristome double; exostome teeth with external surface cross striolate proximally, papillose distally; endostome basal membrane high, segments narrow, keeled, cilia 1–3, approximately same length as segments, sometimes absent. Calyptra: naked. Spores: spheric to ovoid, minutely papillose. North America, Mexico, Central America, South America, Europe, Asia, Africa, terrestrial habitats at low to high elevations predominately in temperate and boreal regions.
Species 7 (4 in the flora). Stems of Herzogiella often have large, thin-walled epidermal cells and smaller, thick-walled, cortical cells in few rows. The axillary hairs have two basal cells and two apical cells; the sparse, papillose rhizoids emerge in the leaf axils or just below, or are often restricted to stem bases. The leaves are rigid, symmetric, concave, and sometimes distally secund at the stem and branch apices; there are sometimes 1–4 alar cells along the margins that are differentiated from the thick-walled, linear-fusiform laminal cells. The inflorescences are near the base of stems; the seta is often twisted; the capsule is usually striate when dry, with a wrinkled neck; the exostome teeth are bordered and internally trabeculate; and the endostome is papillose.