Schistidium is a genus of plants in the moss family. While most of the species seem to be Holarctic, there are Middle American and southern Neotropical records of the family. It is well known in Europe, but scarce in Africa and Madagascar. Yet poorly known from northeast Eurasia. About 150 species are recognized. The team of scientists who described the new species was led by Paola Rumin from the Norwegian Institute of Bioeconomy Research, Bergen, Norway and others from: the Stuttgart State Museum of Natural History, Botany Department, Stuttgart, Germany; The University of Arizona Herbarium, Tucson, Arizona, U.S.A.; and the University of Molise, Department of Biosciences and Territory, EnviXLab in Campobasso, Italy.
Schistidium arizonense was described as a new species from the U.S. states of Arizona, New Mexico, and Texas in April of 2026. It belongs to the section Atrofusca, but unlike most other taxa in the section, it is not a pure calcicole (calcium-loving) species. It also occurs on acidic substrates. Based on ITS sequences, the taxon is closely related to S. helveticum, which is congruent with morphological similarities (similar size, the lack of stomata, and mostly absent or short hairpoints on vegetative leaves). Schistidium arizonense is, however, most likely to be confused with the widespread and highly variable S. crassipilum, which appears to be more distantly related.
Citation.
Paola Rumin, Isaac Tiselius, Ries Lindley, Hans H. Blom, and Thomas Kiebacher 2026. Schistidium arizonense sp. nov. (Grimmiaceae), a new xerophytic species from the southwestern U.S.A. related to the Eurasian S. helveticum. The Bryologist 129(1), 35-49, (16 April 2026). https://doi.org/10.1639/0007-2745-129.1.035
