[Wikipedia] Ecological Role: Grimmia pulvinata is a pioneer species, meaning it is among the first organisms to colonize habitat which has been disturbed by an event such as a forest fire.[4] Its resistance to pollution allows it to colonize urban areas such as roofs, walls, and tarmac. (link added by Mary Ann Machi)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2024. Berkeley, California:The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 11/03/2024).