Orders are, with few exceptions, the names of genera with the termination /-aceæ/, as: /Ulvaceæ/, from the genus /Ulva/. /Ectocarpaceæ/, from the genus /Ectocarpus/. /Gigartinaceæ/, from the genus /Gigartina/. [pg029] Suborders, or groups between orders and genera, terminate in /-eæ/. Names of genera are nouns or words taken as nouns. They are derived from any source,—from prominent or peculiar characteristics, from localities, or from names of botanists,—or they may be wholly arbitrary. Personal generic names are divested of titles and take a final /a/, or, in many cases, for euphony, /ia/. Thus, /Ulva/ is the Latin for "sedge"; /Ectocarpus/ is from two Greek words meaning "fruit outside"; /Corallina/ means "coral-like"; /Grinnellia/ is named for Mr. Henry Grinnell. The specific names are commonly adjectives, but sometimes they are nouns, and occasionally are the names of the botanists who first described the plants, in which case the name terminates in /-i/ or /-ii/. The specific name always follows the generic name, thus: /Ectocarpus Hooperi/, a species of /Ectocarpus/, first described by Mr. Hooper. /Grinnellia Americana/, a species, peculiar to America, of a genus named for Mr. Grinnell. /Griffithsia corallina/, a species resembling coral, and belonging to a genus named for Mrs. Griffiths. With regard to the four subclasses mentioned above, it should be said that algæ are strictly classified in accordance with their methods of reproduction; but since allied species have, with few exceptions, the same color, the classification by colors is generally adopted as convenient and sufficiently precise. Familiar, or, in technical language, "vulgar," names are very generally given to land plants, and especially to flowers; but seaweeds are less in sight than flowers are, and so, save in a few instances, have not been named except by the man of science. To remember the scientific names will not be found difficult, for without effort or special pains to acquire the new vocabulary, the names, like those of new personal friends, will insensibly become fixed in the memory. In the body of this work each of the groups (class, subclass, order, etc.), in the classification of both animals and plants, is indicated by a special kind of type. [pg030] VIII DISTRIBUTION OF ALGÆ The eastern coast of North America has been divided into four sections, which correspond to the distribution of the algæ which are characteristic of each section. The boundary-lines are not precise, since some species of each section extend beyond the defined limits; but arctic forms are not generally found south of Cape Cod, nor can tropical varieties be expected north of Cape Hatteras. On the intervening coast, however, there are some species common to both sections. The divisions are: (1) Greenland to Cape Cod; (2) Cape Cod to Cape Hatteras; (3) Cape Hatteras to Cape Florida; (4) the Florida Keys and the shores of the Gulf of Mexico.