Sixth edition, revised and extended west-ward to the 100th meridian. By Sereno Watson, Harvard University, and John M. Coulter, Wabash College, assisted by Specialists in certain groups. Ivison, Blakeman & Co. Pp. 760. Botanists have waited long for the revision of Gray's Manual. The fifth edition was prepared in 1867, since which time there has been remarkable activity among collectors, and a considerable introduction of European species has taken place. The new edition, now that it has come, is better for the delay, for it is an epitome of prolonged labor in almost every department of our varied 6ora. In the main, the new edition adheres to the style of previous ones, although a few innovations have been made ; but all the essential and important features of the last edition have been maintained, and the new ones are decided improvements. The introduced species have been set in different type from the body of the work, and they are not numbered under the genus. They now strike the eye at once, presenting a graphic representation of the proportion which they bear to the native flora, and affording some aid to the student in analysis.

A comparison of this edition with previous ones affords some interesting data of the migrations of plants. In twenty years, not only have many species new to the territory come in from foreign countries, but what is more interesting, several species of the western states have spread eastward. A noticeable feature in such comparison, also, is the large number of high northern plants which have been discovered in recent years inside our northern borders. Some of these have been but recently discovered on the American continent. This fact, and the large number of wholly new species which have been described from our territory in the last twenty years, indicates that field botany is still but imperfectly known, even in the oldest portion of our country.

Several specialists have contributed to the volume in certain critical groups. M. S. Bebb has elaborated the willows, Professor D. C. Eaton the ferns, and Professor L. H. Bailey the sedges. The Hepaticae, or liverworts, have been included, this portion being contributed by Professor L. M. Underwood.

The range of the volume has been extended westward to meet the eastern limit of Coulter's Manual of Rocky Mountain Botany.

Gray's Botany Revised.

New Species.