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Orthotrichum Moss (Orthotrichum stramineum)


Orthotrichum stramineum  is a leaf species described by Hornschuch in Bridel in 1827. Orthotrichum stramineum is part of the Orthotrichum genus and the Orthotrichaceae family.  According to the Finnish Red List is the species vulnerable in Finland. The species is reproducingin Sweden. The habitat of the species is natureforests. No subspecies are listed in theCatalog of Life. Orthotrichum stramineum, This delightfully neat-looking Orthotrichum species usually grows in rounded cushions 0.5-1 cm tall, topped with abundant capsules that sit just above the level of the leaves. Leaves are 2.5-3 mm long, and capsules are 2 mm long. From late winter to early summer, these have a very pale, dull yellowish calyptra, with a contrasting dark red-brown tip and very sparse hairs. Later in the year, the old, furrowed capsules are dark orange-brown, abruptly narrowed below a wide mouth, and then wide again below. They have 8 reflexed outer peristome teeth, and a microscope reveals immersed stomata. Careful examination with a hand lens should show several long hairs around the base of the seta: an almost unique feature among British Orthotrichum species. It is easy to imagine that O. affine (p. 647) with a rather dark tip to its calyptrae is O. stramineum, but the real thing is convincingly striking (if in doubt, check the stomata). The neat growth form of O. stramineum is a good pointer, although it sometimes grows in more irregular tufts like O. affine. O. pulchellum (p. 652) also has dark-tipped calyptrae, but there is a series of dark dots around the bottom of the calyptra (absent in O. stramineum); it also differs in having capsules held clear of the leaves, and leaves that crisp when dry. The overall appearance of O. pallens (Smith, p. 676) is similar to that of O. stramineum, but its calyptra is brighter yellow, with a bright orange tip, and completely lacks hairs. It is usually blunter-leaved than O. stramineum, but sometimes has a short, blunt point on the tip of its leaves. A few populations have slightly darker calyptrae, making microscopical checking even more essential. O. stramineum favours the upland edge more than O. affine, and is the predominant Orthotrichum of trees and shrubs in parts of mid-Wales and eastern Scotland. It is particularly frequent on the trunks of ash trees (Fraxinus excelsior) and on branches of hazel (Corylus avellana), but may be found on all manner of hosts. It is strikingly scarce in oceanic areas, and is almost absent from Ireland.

Taxonomic tree

  • Domain: Eukarya

    • Kingdom: Plantae

      • Phylum: Bryophyta

        • Class: Bryopsida

          • Order: Orthotrichales

            • Family: Orthotrichaceae

              • Genus: Orthotrichum