4. Funaria polaris Bryhn, Bryoph. Itin. Pol. Norv. 70. 1906.
Plants 2-5 mm, with a basal short antheridial branch, green. Leaves 1.7-2.5 mm, concave, clustered at the apex of the stem, ovate, oblong-ovate to obovate, abruptly narrowed to a short, acuminate tip, margin entire; costa ending in the acumen, sometimes as a minute reflexed apiculum; distal laminal cells hexagonal to rhombic-hexagonal, becoming elongate proximally, little differentiated at the margins. Seta 8-15 mm, flexuose curved to cygneous or sigmoid, hygroscopic. Capsule 1.5-2 mm, pyriform from a short neck, generally pendent from the strongly curved seta, mouth oblique on the weakly curved capsule, somewhat sulcate when dry and empty, annulus revoluble, operculum scarcely convex; peristome inserted below the rim of the mouth, teeth lanceolate, golden brown basally and hyaline at the tips, trabeculate and scarcely striolate papillate basally, weakly appendiculate and nearly smooth in the hyaline portion; endostome segments smooth, short and blunt extending from a narrow basal membrane less than 1/4 the length of the exostome. Calyptra cucullate, rostrate, smooth. Spores 18-23 µm, very finely papillose.
Mineral soil or sand, often at the entrance to lemming burrows; low to moderate elevations; Greenland; N.W.T., Nunavut, Yukon; Alaska.
Two small species of Funaria with variously contorted setae, F. polaris and F. arctica, occur at higher latitudes in North America. Both occur on mineral soil, sand, or gravelly sand in moist situations such as river banks but, so far, only the former is known from the entrance of lemming burrows although it has been collected elsewhere. As seen through a hand lens, the two species can be separated in the field by the attenuated leaf tip of F. polaris in sharp contrast to the broad and blunt leaves of F. arctica.