^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. ORDER =RHODYMENIACEÆ= SUBORDER ~SPHÆROCOCCEÆ~ GENUS ^Gracilaria^ ^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.) GENUS ^Hypnea^ ^H. musciformis^ ("moss-like"). Frond six to twelve inches long; main stem running through, thick below and tapering to the size of a bristle; much and irregularly branched, especially at the base; branches wide-spreading in every direction, and longest at the base; branches branch again in the same manner; all parts beset with short, horizontal spines; color purplish-red. A characteristic feature, by which the plant can easily be distinguished, is that the ends of the long branches are naked and are turned over like a hook, or nearly twisted. It is found washed ashore, often in large, intricately twisted tufts, from Cape Cod southward and on the Pacific coast. [Illustration: PLATE XXI. Euthora cristata. Rhodophyllis veprecula. Rhabdonia tenera. Gracilaria multipartita.] [Illustration: PLATE XXII. Rhodymenia palmata. Rhodymenia palmata. Lomentaria Baileyana. Chylocladia articulata.] SUBORDER ~RHODYMENIEÆ~ GENUS ^Rhodymenia^ ("/Red membrane/") ^R. palmata^ ("hand-shaped"). The plant commonly known as dulse. Frond rises from a disk in a short cylindrical stem which spreads into a thin, broad, fan-shaped membrane six to twelve inches long and four to eight inches wide at the top; deeply and irregularly cleft into many wedge-shaped segments; margin usually entire, but often with leaflets; ends of segments indented, showing where divisions will ultimately occur; color dark purplish-red. It grows on rocks and on algæ below low-water mark, and is common on the New England and California coasts. This is an edible alga, and, like /Chondrus crispus/, is an article of food in seaports. (Plate XXII.) GENUS ^Lomentaria^