Plants medium sized to rather large, forming dense tufts, dark green or reddish-green, often glossy. Stems erect, few to several branched; central strand present. Leaves mostly erect, flexuose to crispate when dry, erect-spreading when wet, oblong-lanceolate, lanceolate or oblong-obovate, apex short to long acuminate; margins plane or undulate, reflexed to recurved below, denticulate, serrulate or serrate distally, rarely entire, strongly to rarely weakly limbate; costae single, ca. 2/3 to long excurrent, mostly weak; median cells rhomboidal to narrowly hexagonal-rhomboidal, smooth, weakly to strongly porose; basal cells quadrate to short rectangular; marginal cells linear in 1-3(4) rows, ± thick-walled. Dioicous. Perichaetia terminal; leaves usually differentiated, larger and narrower. Setae elongate, to 4 (5) cm long. Capsules erect to suberect or horizontal, urn cylindrical-obloid or -pyriform, neck narrowly short to long, rarely inconspicuous; opercula convex-apiculate or conic-plano; peristome double, exostome broad and joined at base, distal 1/4-1/3 abruptly narrowed; endostome basal membrane rather high, segments forked distally, cilia reduced or absent. Calyptrae cucullate. Spores lightly to densely papillose.

Plantas medianas hasta bastante grandes, formando manojo densos, de color verde oscuro o verde-rojizo, a menudo brillante. Tallos erectos, con pocas a varias ramificaciones; cordón central presente. Hojas generalmente erectas, flexuosas hasta crispadas en seco, erecto-extendidas en húmedo, oblongo-lanceoladas, lanceoladas o oblongo-obovadas, ápices corto hasta largo-acuminados; márgenes planos o undulado, reflexos hasta recurvados hacia la base, distalmente denticulados, serrulados o serrados, rara vez enteros, marcadamente hasta raras veces débilmente limbadas; costa simple, ocupando aproximadamente 2/3 de la longitud de la lámina hasta largo-excurrente, generalmente débil; células mediales rómbicas hasta angostamente hexagonal-romboidales, lisas, débilmente hasta marcadamente porosas; células basales cuadradas hasta corto-rectangulares; células marginales lineales en 1-3(4) filas, con paredes ± gruesas. Dioicas. Periquecios terminales; hojas generalmente diferenciadas, mayores y más angostas. Setas largas, hasta 4 (5) cm de largo. Cápsulas erectas hasta suberectas u horizontales, urna cilindrico-obloide o -piriforme, cuello angostamente corto hasta largo, rara vez diferenciado; opérculo convexo-apiculado o cónico-plano; peristoma doble, exostoma ancho y unido en la base, abruptamente angosto en los 1/4-1/3 distales; membrana basal del endostoma bastante alta, segmentos divididos distalmente, cilios reducidos o ausentes. Caliptra cuculada. Esporas ligeramente a densamente papilosas.

Keys modified from Ochi (1980).

1. Leaves oblong-lanceolate or lanceolate … 2.

1. Leaves ovate-oblong or oblong … 5.

2. Plants lustrous; laminal cells much narrower, 11-13 µm, abruptly broader and shorter toward the base, then subquadrate; spores 22-26 µm … 3.

2. Plants hardly lustrous; laminal cells rhomboidal-hexagonal or hexagonal, more than 14 µm wide, gradually larger and rectangular in the basal part; spores large … 4.

3. Leaves ± fleshy, acuminate & apiculate; costa ceasing somewhat to far below the apex … A. seminerve

3. Leaves soft, very long acuminate; costa very long excurrent and aristate … A. lanceolatifolium

4. Leaves not bordered, costa nearly percurrent or excurrent; laminal cells 14-16 µm wide … A. heteroneuron

4., Leaves bordered, costa ceasing far below the apex, laminal cells 22-26 µm wide … A. sprucei

5. Leaves short-acuminate; costa excurrent … 5.

5. Leaves long-acuminate; costa nearly percurrent or shorter … 7.

6. Capsules oblong-pyriform with an inconspicuous neck … A. subrotundum

6. Capsules clavate with a conspicuous, slender neck … 8.

7. Leaves indistinctly bordered in 1-2 cell rows; costa short-excurrent; laminal cells 10-12 µm wide … A. exaltatum

7. Leaves distinctly bordered in 2-3 cell rows; costa long-excurrent; laminal cells 14-18 µm wide … A. megalocarpum

8. Leaves with strongly undulate margins … A. ramicola

8. Leaves with nearly plane margins … 9.

9. Leaves strongly denticulate in the upper part … A. pallidum

9. Leaves crenulate or serrulate in the upper part … 10.

10. Plants usually large to medium-sized; leaf tip ending in a long capillary apiculus; border distinct; costa ending below the apex; operculum swollen, hardly apiculate … A. lonchotrachylon

10. Plants usually robust; leaf tip ending in a short apiculus; border indistinct; costa ending far below the apex; operculum apiculate …. A. longifolium