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Bryum: An Overview of Thread-Mosses

Bryum is a diverse genus of mosses belonging to the family Bryaceae. These mosses are found worldwide and exhibit a variety of growth forms and ecological roles.

Taxonomy and Nomenclature

• Genus: Bryum
• Family: Bryaceae
• Common Name: Bryum moss
• Symbol: BRYUM2

The genus Bryum is considered one of the largest moss genera, potentially containing over a thousand described species. However, it's worth noting that some species have been reclassified into segregate genera by Spence.

Species Spotlight

• Bryum argenteum:
  • Common Name: Silvergreen bryum moss, silver-moss
  • Synonym: Bryum argenteum Hedw.
  • Taxonomic Serial No.: 15984
• Bryum capillare:
  • Common Name: Capillary Thread-moss
• Bryum dixonii:
  • Common Name: Dixon's Thread-moss
  • Authority: Cardot ex W.E.Nicholson
  • Taxon Version Key: NHMSYS0000309489
  • Rank: Species
  • Distribution: Endemic to Scotland, occupying montane habitats.
• Bryum miniatum:
  • Common Name: Red thread-moss (glossy red bryum moss)
• Bryum dichotomum:
  • Other Name: Bryum bicolor
• Rosulabryum capillare:
  • Alternative Name: Bryum capillare

Distribution and Habitat

• Bryum mosses are found globally.
• Bryum argenteum, for example, has a cosmopolitan distribution.
• Some species, like Bryum dixonii, are endemic to specific regions (Scotland).
• Habitats range from woods and sheltered grassy areas (Rhodobryum roseum) to montane regions (Bryum dixonii).

Morphological Characteristics

• Bryum mosses often grow in tufts or patches.
• Stems are typically 1 to 3 cm tall.
• Dry plants of some species, like some Bryum, may have corkscrew-like shoots, with leaves spirally twisted around the stem.
• Bryum argenteum forms compact tufts or cushions that appear silvery-grey.

Ecological Role

• Bryum argenteum is an important component of Biological Soil Crusts (BSCs) in some desert environments.
• Bryum argenteum can be considered a weed in certain contexts, such as on putting greens.
• In the Netherlands, Baltic bryum is listed as susceptible on the Red List of Dutch mosses, 2013.

Interactions with Other Organisms

• Bryum argenteum may depend on epiphytic bacteria for freezing protection in Antarctic environments.
• Waitea circinata is a fungal pathogen that can affect Bryum mosses in turfgrass.

Genetic Information

• The RAPD technique has been used to assess genetic diversity in Bryum pseudotriquetrum.

Further Information

• Jepson eFlora for CA Vascular Plants, University of California
• Encyclopedia of Life
• Discover Life
• AusMoss