WEBMay 23, 2020 · Moss growing on rocks in the Rock Walk, Wakehurst. 1. They're ancient plants. Mosses are non-flowering plants which produce spores and have stems and leaves, but don't have true roots. Mosses, and their cousins liverworts and hornworts, are classified as Bryophyta (bryophytes) in the plant kingdom. They date back 450 …