A close look at rocks and trees is often rewarded by the orange or yellow mosaic patterns of some of California's 1,000 species of lichens; yet few people know anything about their unusual compound nature (part alga, part fungus) and most lichens don't even have common English names. This convenient guide, the first ever on California lichens, describes the appearance, habitats, and ranges of over 350 species, 48 of which are illustrated in color, with many others shown in black and white. For weavers and fabric manufacturers, the brilliance of lichen colors provides unusual textile dyes. For scientists, the sensitivity of lichens to air pollution makes them useful biomonitors for environmental studies. For nature lovers they can be an unending source of fascination, and Lichens of California offers convenient identification keys, range maps, and chapters describing the structure, chemistry, and ecology of lichens.