Plants to 15 mm. Stem central strand strong. Leaves oblong-ovate to oblong-lanceolate, keeled or concave, margins plane, costa prominent; juxtacostal and marginal basal laminal cells hyaline; distal lamina 2-stratose (1-stratose for G. plagiopodia). Gemmae absent. Sexual condition autoicous (G. crinitoleucophaea dioicous). Seta arcuate to sigmoid (except G. americana), eccentrically attached to capsule. Capsule immersed, smooth, ventricose; stomata 3-4, large, at base of capsule. Calyptra mitrate, just covering operculum.

Species 4 (4 in the flora): North America, Mexico, Central America, South America, Eurasia, n Africa, Pacific Islands (New Zealand), Australasia, Antarctic.

Members of subgenus Gasterogrimmia are recognized by their commonly occurring immersed, ventricose capsules on arcuate to sigmoid setae that are eccentrically attached. Additionally, all these species have three to four large stomata at the very base of the capsule. The entire basal region of the leaf is typically hyaline. Most members of the subgenus are restricted to calcareous habitats. The genus Jaffueliobryum is the only other group in the Grimmiaceae to be so strongly tied to calcareous substrates.

Lower Taxa

• Grimmia americana E. B. Bartram
• Grimmia anodon Bruch & Schimper
• Grimmia crinitoleucophaea Cardot
• Grimmia plagiopodia Hedwig