Bryum argenteum, the silvergreen bryum moss or silvery thread moss, is a species of moss in the family Bryaceae. It is one of the most common mosses of urban areas and can be easily recognized without a microscope.

Light and Moisture Lighting should be indirect; direct sunlight is the nemesis of moss spores. Water from below to avoid washing away your future moss colony. A shallow tray with 1/4-1/2 inch of water does the trick, allowing the substrate to soak up moisture without becoming waterlogged.

Growing Conditions and Distribution: Bryum argenteum is a cosmopolitan species common to urban areas where it can be found between cracks on sidewalks, poor soil, and rocks. It can be found in more natural settings as well, however it has come to thrive better in anthropogenic habitats.

Plants are small to medium - sized, 1 - 25 mm long. The stems are julaceous (smoothly cylindrical, like a catkin), 1-25 mm tall, yellowish green or red to red-brown, and branched below. The leaves are crowded and tightly held to the stem, overlapping each other, broadly ovate and concave and green below.