^E. cristata.^ Frond one inch to five inches high, membranaceous, broadly spreading; divisions wide and numerous, ultimately becoming fine like minute branchlets, each one of which, under a glass, shows a notch in the tip. This beautiful, bright-red alga is found in abundance north of Cape Cod. It differs from /Delesseria alata/ in having no midrib or veins. It grows in deep water on stones, shells, and algæ. (Plate XXI.)
^R. veprecula.^ Frond two to five inches long, one fourth of an inch to one and one half inches broad, membranaceous, forked; margin covered with leaflets which are in turn edged with minute branchlets; color deep red. It is found on the northern New England coast. (Plate XXI.)
^R. tenera.^ Frond six to eighteen inches long, cylindrical, fleshy, translucent, juicy; irregularly and profusely branched, branches longest at the base, erect, tapering at both ends, numerous branchlets; sometimes the main stem runs through the plant, sometimes it is lost in the [pg084] branching; spore-masses sometimes form knotty bunches on the side of branches. It resembles a large /Cystoclonium purpurascens/. It is characteristic of Long Island Sound, and is not found north of Cape Cod, but common from there southward along the whole Atlantic coast. (Plate XXI.)
^R. Coulteri.^ This species is common on the Pacific coast, and differs from /R. tenera/ in having a more pronounced leading stem, and branches shorter and crowded at the top of the frond.
^E. isiforme.^ Frond grows in tufts a foot or more in diameter; stems branch in all directions from a central point, and taper gradually to the end; secondary branches spread to all sides; all branches swollen at intervals and armed with several spines spreading from a conical base; color dark red, becoming on exposure orange or yellow, and at length semi-transparent and horn-like; substance firmly cartilaginous. Abundant at Key West.
^G. multipartita^ ("many times divided"). Frond four to twelve inches long; starting from a short, cylindrical stem, it flattens and broadens as it rises, dividing in an irregular, forking manner, or cleft into palmate segments which broaden as they rise, and which divide in the same manner; often cleft or branched on the edges; conical spore-masses scattered over the frond during July and August; dingy purple in color. The plant is variable and sometimes is difficult to determine. It is common from Cape Cod southward. A narrow variety is most abundant in Long Island Sound. In Florida and on the California coast there are broad varieties which may be mistaken for /Rhodymenia/. (Plate XXI.)