Didymodon spp.

didymodon mosses

Pottiaceae Worldwide (dry, base-rich, urban)

Native to North America

SunFull Sun – Part Shade

WaterLow

Overview

Didymodon spp. is a genus of small acrocarpous mosses in the family Pottiaceae, growing on soil, rock, walls, mortar, and disturbed ground in many regions, often in dry, calcareous, or urban habitats. The plants form low green, yellow-green, or brownish turfs and cushions usually 0.2-1.2 inches (0.5-3 cm) tall. The narrow, lance-shaped leaves taper to a point and curl, twist, or press against the stem when dry, spreading or curving back when moist; in many species the leaves break easily, and the broken tips serve as a means of spread. The leaf cells are small and often bulging, a feature of the family. Didymodon spp. tolerates drought, heat, and pollution well, and several species are common on pavements, walls, and roadsides in towns, including limestone mortar. Spore capsules are cylindrical and held upright on stalks but are produced only in some species; much spread is by broken leaves and shoot fragments. The genus favours base-rich, often dry and disturbed sites that many plants avoid. Telling the many species apart relies on microscopic leaf characters, and the genus has been repeatedly reclassified.

Native Range

Didymodon spp. is widespread across many regions of the world, growing on soil, rock, walls, mortar, and disturbed ground, often on dry, base-rich, or calcareous substrates. Several species are common in towns on pavements, walls, and roadsides.

Suggested Uses

Didymodon spp. colonises walls, paving, mortar, and disturbed ground on its own and is used in studies of urban and pollution-tolerant mosses. The genus indicates dry, base-rich habitats. Its drought tolerance makes it a subject of interest for green roofs and stonework in dry, sunny sites.

How to Identify

Identify by the low green to brownish turfs of small shoots with narrow, lance-shaped leaves that taper to a point and twist or press to the stem when dry, often with easily broken tips. The genus favours dry, base-rich, and urban surfaces. Microscopic leaf-cell features separate the many species and the genus from related Pottiaceae.

Appearance

Colors

Foliage Colors

green

yellow green

Bloom Information

Mosses do not flower. Didymodon spp. reproduces by spores from cylindrical capsules held upright on stalks in some species, while many spread mainly by broken leaf tips and shoot fragments that root and grow. Capsule production varies widely among species.

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

Low

Care & Maintenance

Care Guide

Didymodon spp. grows on soil, rock, walls, and mortar in sun to part shade, tolerating drought, heat, and pollution better than most mosses, and favouring base-rich or calcareous surfaces. It survives dry spells by drying out and reviving when wetted. The genus appears on its own on stonework, paving, and walls, including in towns, and is rarely deliberately grown. Deep shade and constantly wet acidic ground reduce it.