Ecology: Lowland to upper montane; in wet or seepy habitats, on soil and rocks. Elevation: 50-3500 m (Venezuela: 180-1200 m, Colombia: 50-3500 m, Ecuador: 310-2800 m, Peru: 100-3100 m, Bolivia: 120-2740 m). Distribution: Southeast United States, Mexico, widespread in the Neotropics.
Ecología: Tierras bajas hasta montano; en hábitats húmedos o con filtraciones, sobre suelo y rocas. Elevación: 50-3500 m (Venezuela: 180-1200 m, Colombia: 50-3500 m, Ecuador: 310-2800 m, Peru: 100-3100 m, Bolivia: 120-2740 m). Distribución: Mundial: sureste de Estados Unidos, México, amplia distribución en el Neotrópico.
Philonotis uncinata is characterized by the rather stiffly erect plants mostly to 2 cm, erect to secund (when dry), oblong- to triangular-lanceolate to ca. 1.5(2) mm, often curved, acuminate to acute (rarely obtuse) apices, revolute, serrate margins throughout, percurrent to short excurrent costa, papillose upper lamina cells that are 10 µm or less wide with papillae strongerly projecting on distal cell ends, dioicous sexual condition, erect setae to 30 mm, and furrowed capsules to 2 mm. Philonotis glaucescens (Hornsch.) Broth. and P. gracillima Ångstr., considered here to be synonyms, have been treated as distinct species or as varieties of P. uncinata. However it is not uncommon among Andean collections to find populations with both or all three taxa (forms), and these often appear to intergrade. The form called Philonotis gracillima (or as P. uncinata var. gracillima) has been confused with P. hastata (Duby) Wijk & Margad., both usually are small plants, exhibiting a bluntly acute or subobtuse apex, however in the latter the median and upper laminal cells are broader (10-15 µm).
Synonyms include Bartramia minuta Taylor, B. versifolia Hampe, Philonotis glaucescens (Hornsch.) Broth., P. gracillima Ångstr. Note: collections in TROPICOS require re-examination, for the present collections can also be found under both P. glaucescens and P. gracillima. Philonotis crassinervia Broth.& Paris (Rev. Bryol. 33: 103. 1906; type from Colombia) appears to be a form of P. uncinata; the lower marginal cells appear to be differentiated, smaller and ± isodiametric, with inner cells larger and ± elongate.
Philonotis uncinata se caracteriza por las plantas erectas bastante rígidas, generalmente hasta 2 cm, erectas a unilaterales (en seco), hojas oblongo- a triangular-lanceoladas hasta ca. 1.5(2) mm, ápice acuminados a agudo (rara vez obtusos), a menudo curvados, márgenes completamente serrados, revolutos, costa percurrente a corto-excurrente, células superiores de la lámina papilosas, tienen 10 µm de ancho o menores, con papilas fuertes proyectándose en los extremos distales de las células, condición sexual dioica, setas erectas hasta 30 mm y cápsulas acanaladas hasta 2 mm. Philonotis glaucescens (Hornsch.) Broth. y P. gracillima Ångstr., son consideradas aquí como sinónimos, han sido tratadas como especies o variedades diferentes de P. uncinata. Sin embargo, no es raro encontrar poblaciones con ambos o los tres taxa (formas) entre las colecciones andinas, y a menudo aparecen formas intermedias. La forma denominada Philonotis gracillima (o P. uncinata var. gracillima) ha sido confundida con P. hastata (Duby) Wijk & Margad., ambas generalmente son pequeñas, que presentan un ápice obtusamente agudo o subobtuso, aunque en la última las células mediales y superiores de la lámina son más anchas (10-15 µm).