fronds remain until frost, often changing from green to variegated shades of brown. There do not seem to be any well-marked variations in this fern. Ruprecht has a “var. _Aleuticum_,” the _Ad. boreale_ of Presl, separated mainly on account of its smaller size and fewer parts. The genus _Adiantum_ contains eighty-three species, according to Mr. Baker’s estimate; but this number is reduced to sixty-seven by the more recent and very careful recension of Keyserling. The species vary in form from a simple and reniform frond an inch or two in diameter to others with ample tripinnate and even quadripinnate fronds. The species with distinctly bipartite and radiated fronds are _Ad. patens_, _hispidulum_, and _fiabellulatum_. _A. patens_ is found in Mexico and Central America. It is a smaller plant than _A. pedatum_, and has deeply-sunken reniform involucres. The other two occur in South-eastern Asia, the _hispidulum_ extending to Africa and to New Zealand, and the _flabellulatum_ to Japan: the former has hispid surfaces and small roundish involucres; and the latter has rusty-fibrillose rachises, coriaceous pinnules, and transversely oblong sub-confluent involucres. _Ad. patens_ follows the form and branching of our fern very closely; but the two Old-World species often depart from it, and show a tendency to develop branches on one or other of the longest pinnæ, thus indicating an approach towards a pyramidal structure of the frond. The remaining _Adianta_ of the United States are _Ad. Capillus-Veneris_ (Linnæus), found from North Carolina to California; _Ad. emarginatum_ (Hooker), which is the _Ad. Chilense_ of American botanists, but not of Kaulfuss, found in California and Oregon; and _Ad. tricholepis_ (Fée), which occurs in Texas and California, and extends southwards to Central America. The American Maiden-hair is easily cultivated, and will grow very freely either in a shaded corner of a garden or in the house, and is perhaps more elegant and graceful than any other of our ferns, the climbing-fern scarcely excepted. Josselyn evidently mistook it for the Venus-hair, one of the chief ingredients in a syrup which was formerly a famous remedy for nearly all ailments, and said, “The Apothecaries for shame now will substitute _Wall-Rue_ no more for Maiden Hair, since it grows in abundance in _New-England_, from whence they may have good store.” Mr. Emerton’s figure is taken from a living plant, and shows the frond as it appears before it has been flattened in a collector’s portfolio. OSTRICH-FERN. [Illustration: ] ONOCLEA STRUTHIOPTERIS, Hoffmann. Ostrich-Fern.