The growing season for most plants is over by the end of fall—even the asters that can persist into December have shriveled and finished their blooming for the season.

Byrum argenteum, or Silver Moss

Entodon seductrix creeping over asphalt

But winter is the season when many mosses are green and reproducing. Easy to see on cold rainy days in January are those that live in the mortar between the concrete in sidewalks and brick walls and in asphalt.
Mosses don’t require much to make a life. A little moisture and a tiny amount of mineral soil, and their spores open to start new growth. These small plants are pioneer species, making a home for the plants that have tubes to transport water (vascular plants). Only one cell thick, they soak up water from the environment. If no water is available, they will be dormant until the next drop arrives. A vigorous population of mosses allows the seeds of vascular plants to sprout; Norie Burnet of Eden Woods in Chesterfield tells visitors that ...