Selaginella cinerascens is a regional endemic that appears confined to southwestern San Diego County and adjacent northern Baja California. It is generally called Ashy Spike Moss because when it dries down it becomes a grayish color. However, it can be confused with S. asprella which is commonly called Bluish Spike Moss but which also dries down to a grayish color. For this reason I believe that currently reported occurrences of S. cinerascens on the eastern side of the Peninsular Mountain Ranges is, in fact, S. asprella.
Calflora map of S. cinerascens and
Calflora map of S. asprella illustrate the overlap of ranges and the general trend of S. asprella to be inland away from the ocean in the Transverse and Peninsular Ranges (its reported occurrence in Orange Co. is from 1923 and is probably S. bigelovii).
The species is currently under threat of continuing habitat loss due to human development. Researchers at San Diego State have conducted studies on its growth and reintroduction but these studies were not carried further than the following links (as far as I know). The species really needs to be cultivated and held in cultivation for reintroduction into managed (exercising full environmental control over the habitat despite natural periods of drought or unseemly weather patterns) reserves. The SDS studies can be read at:
The 1996-1997 Restoration Study
The 1997 Restoration Study
The 2000 Follow Up to the 1997 Restoration Study
Please note that in making their assessments of the vitality of S. cinerascens the students failed to consider that in developing an approach at a methodology of cultivation that they relied upon the research done upon Selaginella species that are members of the Stachygynandrum, an entirely different type of Selaginella and upon apparently techniques used in the propagation of mosses. Both are entirely unsuitable for the propagation of members of the Tetragonostachys.
Let me introduce you to this charming little plant:
Rolf Muertter has an excellent close up of a colony of the species on Flickr
while it is green! If you look carefully strobili are visible throughout the image, they are the broad leafed upright structures (part of one is visible on the bottom about 1/4 right of the lower left corner).
S. cinerascens-green
The San Diego State study generated an image of a colony when it was green and when it was dried.
S. cinerascens-green/dry states
A commonly encountered type of image of the species at CalFlora
S. cinerascens in partially dry state