Orthotrichum spp.
bristle mosses
Temperate and montane regions, both hemispheres
Native to North America
SunPart Shade
WaterMedium
Overview
Orthotrichum spp. is a genus of acrocarpous mosses in the family Orthotrichaceae, the bristle mosses, comprising well over 100 species spread through temperate and montane regions of both hemispheres. Plants form small, rounded cushions or erect tufts 0.2-2 inches (0.5-5 cm) tall, dark green to brownish-green, growing mainly on tree bark and, in some species, on rock. Stems are erect and sparingly branched, clothed in lanceolate leaves 1.5-4 mm long that curve inward and twist when dry and spread when moist; leaf margins are often recurved and the surfaces bear tiny bumps called papillae. Spore capsules are held erect, partly sunk among or raised just above the leaves on short stalks, and are ribbed or furrowed when dry, ripening through spring and summer. A hood-like calyptra covers the young capsule and carries short hairs in many species, the feature behind the common name bristle moss. Many species grow as epiphytes and are sensitive to sulphur dioxide and other air pollutants, so their presence and abundance track local air quality. Species are separated by capsule ribbing, peristome teeth, and stomatal position, work that often needs a microscope. As non-vascular plants they lack true roots and take up water across their surfaces.
Native Range
Orthotrichum spp. is widely distributed across temperate, boreal, and montane regions of both the Northern and Southern Hemispheres. The genus is well represented in Europe, North America, and Asia, growing on tree trunks, branches, and exposed rock. It is largely absent from hot lowland tropics.Suggested Uses
Orthotrichum spp. is used by ecologists as a bioindicator of air quality because several species are sensitive to pollution. The cushions add to bark and rock communities in moss gardens and naturalistic plantings. The genus also contributes to bark micro-habitats that shelter small invertebrates.How to Identify
Appearance
Bloom Information
Mosses do not flower. Orthotrichum spp. reproduces by spores from capsules that mature mainly in spring and summer. Capsules develop after fertilization in moist conditions and shed spores as they dry and the lid falls.
Detailed Descriptions
Foliage Description
dark green to brownish-greenGrowing Conditions
Sun Requirements
Requires 2-6 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight