They are found in greenhouses and in natural areas adjacent to springs and outfalls along rock surfaces. Color can range from a brilliant pink to an olive drab. Of economic importance is Porphyra . Due to its value , the life history of Porphyra has been extensively examined. The foliose flat blade that comprises the dominant growth form is haploid.
Growth is during the colder parts of the year.
During reproduction, the haploid plant produces spermatia along the borders of the plant. Although plants can produce either spermatia or carpogonia, generally a plant produces one or the other. Plants producing spermatia appear to have a whitish margin that look as if the plant is old. The tissue is a large array of cells that are producing colorless spermatia. Plants that produce carpogonia are in close position to those producing spermatia.