Selaginella are evergreen rhizomatous, mat-forming perennials. They may be small and tufted, or tall and scrambling, with slender stems covered with small scale-like leaves - often fernlike. They develop spores in short terminal spikes. There are many different varieties, and they vary hugely in size, and in the way they grow. Most like high humidity. Willdenow's spikemoss changes colour depending on the light, from greens to blue-greens