Ptychostomum capillare (Capillary Thread-moss)

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Ptychostomum spp.

ptychostomum mosses

Bryaceae

Worldwide (disturbed and nutrient-rich ground)

Native to North America

SunFull Sun – Part Shade

WaterMedium

Overview

Ptychostomum spp. is a genus of acrocarpous mosses in the family Bryaceae, made up largely of species formerly placed in Bryum spp.. The plants form low green to yellow-green tufts and turfs usually 0.2-2 inches (0.5-5 cm) tall, often with a reddish base, on soil, rock, walls, paths, dunes, and disturbed ground in many regions. The egg-shaped to lance-shaped leaves are concave and spirally set around the stem, frequently bordered by narrow cells and tipped with a short point, becoming twisted when dry. Like other Bryaceae, the genus bears rounded, nodding spore capsules on long reddish stalks that hang like small urns. Ptychostomum spp. was separated from Bryum spp. on the basis of molecular and microscopic studies, and includes many common, weedy mosses of gardens, pavements, and waste ground. Several species spread by bulb-like gemmae as well as by spores, letting them colonise bare ground quickly. The genus favours open, often nutrient-rich or disturbed sites and tolerates drought by drying out and reviving when rewetted. Telling Ptychostomum spp. from Bryum spp. and other segregate genera usually needs a microscope.

Native Range

Ptychostomum spp. is widespread across many regions of the world, growing on soil, rock, walls, paths, dunes, and disturbed ground. Many species are common in gardens, pavements, and waste ground in temperate and urban areas, often on nutrient-rich or disturbed sites.

Suggested Uses

Ptychostomum spp. species are grown in moss gardens, green roofs, and terraria for quick low cover, and pioneer species help stabilise bare and disturbed ground. The genus is used in bryophyte study and in tracking the reclassification of Bryum spp.. Weedy species colonise paving, gravel, and cleared soil without help.

How to Identify

Identify by the low green to yellow-green tufts with reddish bases and concave, spirally arranged, short-pointed leaves that twist when dry, bearing rounded nodding capsules on long reddish stalks. The genus closely resembles Bryum spp., from which it was split, and separating the two usually requires microscopic leaf and capsule features.

Appearance

Colors

Foliage Colors

green

yellow green

Bloom Information

Mosses do not flower. Ptychostomum spp. reproduces by spores from nodding capsules ripening mainly in spring and summer, and many species also spread by bulb-like gemmae produced among the leaves or on underground shoots. Vegetative spread is common in weedy 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

Medium

Care & Maintenance

Care Guide

Ptychostomum spp. grows on open soil, rock, walls, and disturbed or nutrient-rich ground in sun to part shade, tolerating poor and compacted substrates. It absorbs water and nutrients through its shoots and survives drought by drying out and reviving when wetted. In moss gardens, green roofs, and terraria, weedy species establish quickly from fragments or gemmae on firm, low to moderate-nutrient surfaces. Dense shade and competition from vascular plants reduce it. Many species appear on their own on paving and bare soil.