Orthotrichum anomalum
anomalous bristle-moss
Europe, North Africa, Asia, and North America
Drought Tolerant
Native to North America
SunFull Sun – Part Shade
Overview
Orthotrichum anomalum is a small cushion-forming moss that grows on lime-rich rock, mortar, concrete, and old walls, where it makes neat dark green to brownish tufts about 0.4-1 inch (1-2.5 cm) high. The narrow, blunt leaves curl and twist when dry and spread out when wet, a common response in mosses that dry out and revive with rain. Unlike most bristle-mosses, which hold their spore capsules among the leaves, this species raises its ribbed, oval capsules above the leaf tips on a short stalk (seta), the feature that gives it the name anomalous. The capsules are pale brown and grooved when dry. As a moss it has no roots, flowers, or vascular tissue and absorbs water over its whole surface, surviving dry spells in a dormant state. It is a lime-loving (calcicole) species, which sets it apart from the many bristle-mosses that grow on bark and acid rock. It tolerates sun, drought, and exposure on hard surfaces, spreading slowly to form patches. Its strict need for calcareous, hard substrates limits where it establishes.
Native Range
Orthotrichum anomalum is widespread across Europe, North Africa, western and central Asia, and North America. It grows on calcareous rock, walls, mortar, and concrete in both natural and built settings. It is common in lowland and upland areas with lime-rich stone.Suggested Uses
Found on lime-rich walls, tombstones, paving, and rockwork rather than being deliberately planted, where it adds green cover to hard surfaces. It contributes to the moss flora of old masonry and limestone. Its need for calcareous, hard substrates makes it unsuited to soil beds or acidic sites.How to Identify
Appearance
Bloom Information
This moss reproduces by spores rather than flowers. Pale brown, ribbed spore capsules are raised on short stalks above the leaves and mature mainly from late winter into spring. When dry the capsules become grooved and release spores to the wind.
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
Water & Climate
Water Needs
Drought Tolerance
Drought tolerant when established