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Bryum spp.

bryum mosses

Native to North America

SunFull Sun – Part Shade

Overview

Bryum spp. is a large, cosmopolitan genus of acrocarpous mosses in the family Bryaceae, with several hundred species growing on soil, rock, walls, paths, and disturbed ground from the tropics to polar regions. Plants form low cushions, turfs, or scattered shoots usually 0.2-2 inches (0.5-5 cm) tall, in shades of green, often flushed red or bronze at the base. The leaves are egg-shaped to lance-shaped, concave, and spirally arranged around the stem, frequently ending in a hair-point and bordered by narrow elongated cells. When dry, the shoots become twisted and the cushions take on a duller tone. The genus is named for its rounded, often nodding spore capsules, which are borne singly on a long reddish stalk and hang like tiny pendulous urns. Many species are pioneers that quickly colonise bare soil, gravel, and burnt ground, and some grow vigorously in nutrient-rich or disturbed urban habitats. Reproduction is by spores and, in many species, by tiny bulb-like gemmae that allow rapid vegetative spread. The genus has been split, with several species moved to Ptychostomum spp. and other segregate genera. Plants survive drying by becoming dormant and reviving when rewetted.

Native Range

Bryum spp. is found on every continent, including Antarctica, growing on soil, rock, masonry, paths, dunes, and disturbed ground from sea level to high mountains. Many species are widespread weeds of gardens, pavements, and waste ground in temperate and urban regions.

Suggested Uses

Bryum spp. species are grown in moss gardens, terraria, green roofs, and bonsai plantings for low green cover, and pioneer species help stabilise bare soil and gravel. Mosses are studied as indicators of air quality and disturbance. Several Bryum spp. species are among the first colonisers of cleared or burnt ground.

How to Identify

Identify by the low green cushions or turfs of upright shoots with concave, spirally arranged leaves often tipped by a hair-point, frequently red-tinted at the shoot base. The rounded, nodding spore capsules on long reddish stalks are characteristic. Microscopic leaf-cell and capsule features separate Bryum spp. from the closely related Ptychostomum spp. and other Bryaceae.

Appearance

Colors

Foliage Colors

green

Bloom Information

Mosses do not flower. Bryum spp. reproduces by spores released from nodding capsules that ripen mainly in spring and summer, and by bulb-like gemmae produced in the leaf axils or on underground shoots. Capsule production varies with species and moisture, and many populations spread chiefly by vegetative gemmae.

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

• 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

Medium

Care & Maintenance

Care Guide

Bryum spp. grows on damp to seasonally dry surfaces in sun or shade, tolerating poor, compacted, and disturbed substrates that few plants colonise. It needs no soil depth and absorbs water and nutrients directly through its shoots, surviving drought by drying out and reviving when wetted. In cultivation for green roofs, terraria, and moss gardens, it establishes from fragments or gemmae on firm, moist, low-nutrient surfaces with good light. Excess fertiliser and dense shade from vascular plants reduce it. Many species spread on their own onto paving and gravel.