DR. ASA GRAY'S _Botanical Series_, New York, Ivison & Phinney, consisting of-- I. _How Plants Grow_, etc., _with a Popular Flora,_ etc. 16mo. pp. 233. II. _First Lessons in Botany and Vegetable Physiology._ 8vo. pp. 236. III. _Introduction to Structural and Systematic Botany and Vegetable Physiology._ 8vo. pp. 555. IV. _Manual of the Botany of the Northern United States, including Virginia, Kentucky,_ etc. 8vo. pp. 636. V. Same as IV., with the _Mosses and Liverworts_ added, illustrated by Engravings, pp. 739. VI. Same as IV., with II. bound up with it. pp. 872. The first-named of these books is a new candidate for public favor; the others are revised and improved editions of books which have already been favorably received. We have sometimes thought that the popularity of a school-book is in inverse proportion to its merits, and are glad to learn that five editions of Dr. Gray's "Structural and Systematic Botany" are witnesses against the truth of this assumption. No man can deny that Dr. Gray's books are all of the highest order of merit. The accuracy and extent of his scholarship are manifest on every page,--a scholarship consisting not merely in an extensive acquaintance with the works of other botanists, but in a careful confirmation of their results, and in additions to their knowledge, by an observation of Nature for himself. His clearness of style is an equally valuable characteristic, making the reader sure that he understands Dr. Gray, and that Dr. Gray understands the subject. In the "Manual" this clearness of style extends to the judicious selection of distinctive marks, whereby allied species may be distinguished from each other. Even the most difficult genera of golden-rods, asters, and grasses become intelligible in this manual; and many a less difficult genus which puzzled our boyhood, with Beck's, Eaton's, and Pursh's manuals, became so plain in Gray, that we cannot now imagine where was the difficulty. The extent of the field which Gray's Manual covers prevents him, of course, from giving such lifelike descriptions of plants as may be found in Dr. Bigelow's "Plants of Boston and its Vicinity," or such minute word-daguerreotypes as those in Mr. Emerson's "Trees of Massachusetts,"--books which no New England student of botany can afford to be without; but, on the other hand, the description of each species, aided by typographical devices of Italics, etc., is sufficient for any intelligent observer to identify a specimen. The exquisite engravings, illustrating the genera of Ferns, Hepaticæ, and Mosses, are also a great assistance.