four feet above the slimy ooze below. And what purpose does this vast sieve-like mass effect? As the tide rushes in it bears with it masses of decaying vegetable matter and detritus of various kinds, which, when the tide runs out, is in large part left behind. These, added to the decaying leaves which are constantly dropping from the trees above, at length build up a slimy bottom, which, eventually rising above the water, in time becomes solid ground and fit for agricultural purposes.

The continuation of

FIG. 4.

this process at last leads to the undoing of the mangrove itself, for, being a lover of the water or of wet places, it finds the new conditions uncongenial and begins to recede, thus vacating the land which it has itself built up, and adding largely, year after year, to the soil available for the purposes of man. In the fourth illustration this stage of the development is depicted. Here may be plainly seen the receding mangrove and the intervening strip of barren land between it and the distant hillside, where the

colony first found a congenial foothold, and from which it has been forced by conditions of its own creating. This barren strip will soon be utilized by man for the growing of crops, and, indeed, the process has already begun, for at the very base of the hill may be seen a small plantation of bananas.

The illustrations accompanying this article were made from photographs taken by the writer on his last journey to Haïti in 1905, and were secured about eighteen miles to the westward of Cap Haïtien.

One hardly

Here then we have the story of the mangrove. realizes as he stands looking at the fringe of one of these swamps that a great work is being slowly but irresistibly carried on year after year. Nor does he fully comprehend how well adapted this plant is to its work, until he studies carefully the structure of its fruit, and its method of forcing itself into the domain of the waters, thus transforming them to the uses of mankind. This work is going on in many parts of tropical America through the agency of the plant known to botanists as Rhizophora Mangle, a name given to it by Linnaeus in 1753. In other parts of the world are other species of the same genus carrying on the identical work, so perhaps the magnitude of the result may be realized. Not only is the mainland extended by this plant, but islands are formed by it. Some of the floating hypocotyls become stranded on reefs or in other shallow places. At first we have perhaps but a single plant, such an one as is represented to the left of the first illustration. This in time forms its network of roots, catching and retaining detritus, and finally is formed a small island, which continues to grow as long as the mangrove can find congenial surroundings. In the shallow waters surrounding the keys of south Florida many islands have been built up in this way, and these in all stages of development may be seen there

now.

There are other land-builders in the tropics, such as the minute coral animals, but perhaps none can excel the mangrove in this work, and certainly in none is the process more apparent.

REVIEWS

Sturgis's The Myxomycetes and Fungi of Colorado.*

This paper is No. 1 of a series by Ellsworth Bethel and William C. Sturgis, entitled "The Myxomycetes and Fungi of Colorado." In the series it is intended to cover the mycological flora of Colorado, including the Rocky Mountain region, which hitherto has been largely neglected by mycologists. In the present paper nearly one hundred species and varieties of Myxomycetes are described. Preceding the descriptions are brief notes on life history, collecting and preservation, microscopic examination, and literature. It is intended that the paper may serve as a beginner's guide, and the key is based upon the synopsis of the orders and genera in Lister's Monograph of the Mycetozoa. C. STUART GAGER.

Hanausek's Microscopy of Technical Products †

This work is the result of the many years of labor of the distinguished expert, investigator and teacher, Dr. Hanausek, analyst of the Governmental Food Laboratory at Vienna. After a brief introduction on the use of the microscope and microchemical reagents, the authors discuss in nine chapters the following commercial products: (1) starch and inulin; (2) vegetable fibers, under which heading attention is also given to the examination of paper; (3) animal and mineral fibers and textile fabrics; (4) stems and roots; (5) leaves; (6) flowers; (7) fruits and seeds; (8) teeth, bone and horn; (9) microchemical analysis for various acids and minerals.

The book is designed as a guide to the student entering the field of technical microscopy and aims to familiarize him with the methods of investigation and to prepare him for independent work. It teaches the technical worker how to investigate microscopically commercial raw materials with reference to their comSturgis, William C. The Myxomycetes of Colorado. Colorado Coll. Publication. Gen. Ser. No. 30. Sci. Ser. 12: 1-43. Colorado Springs, Colo., 1907. † Hanausek, T. F. The Microscopy of Technical Products. Revised and translated by Andrew L. Winton, with the collaboration of Kate G. Barber. Pp. xii + 471. f. 1-276. John Wiley and Sons, New York, 1907. $5.00.

*

position and suitability for technical purposes, thus enabling him to reach practical conclusions. The origin, harvesting, preparation and utilization of material are also briefly considered whenever the methods of preparation have an influence on the structure of the raw material.

The English edition has been improved by the introduction of over forty new cuts. The drawings by Winton and Barber are decided improvement over many in the original work which are occasionally so diagrammatic as to be almost misleading. Note should also be made of the very considerable additions to the chapter on textile fibers and of the discussion of commercial timbers which has been revised and extended so as to include the most important North American species.

Noteworthy features of the book are the citations of the literature dealing with the various topics treated and the attention that is given to the solution of purely practical problems. Mention should also be made of the discussions of the more important morphological and biological features of the various organs and structures studied so that the student begins his examination of the commercial products with an understanding of the nature and origin of the various cells and tissues with which he is dealing. While in some minor respects this treatment is not in accord with present day botanical teaching, it will be conceded that the presentation has been made with a clearness and conciseness of statement and with a simplicity and consistency of terminology that may well serve as models for future authors.

Considering the range of the work, the authors have been remarkably successful in handling the various topics and have furnished to technical microscopists a timely and valuable textbook. CARLTON C. CURTIS.

PROCEEDINGS OF THE CLUB

FEBRUARY 26, 1908

The Club was called to order at the Museum of the New York

Botanical Garden at 3:45 P. M. Ten persons were present.
After the reading and approval of the minutes of the preceding

meeting, resignations were read and accepted from Mr. W. H. Liebelsperger, Mr. J. Charles Roper, Mr. James Walker, Mr. George Wirsing, and Dr. H. E. Hasse. These resignations were accepted by the Club.

The scientific program consisted of two papers, of which the authors have submitted the following abstracts:

Remarks on the Genus Boletus. By Dr. William A. Murrill. This paper will be published in the March (1908) number of TORREYA.

Some Fern Hybrids. By Mr. Ralph C. Benedict.

The object of this paper was to present general facts regarding fern hybrids, to indicate the apparent significance of the facts, and to show examples of some native hybrids.

The literature on the subject seems to be very scanty, and consists principally of scattered descriptions of natural and horticultural hybrids. Lowe (Fern Growing) has given a general discussion of the subject but his work is of a horticultural, rather than of a scientific, value. The most conclusive experiments are those carried on by Miss Margaret Slosson, in which she reproduced culturally Asplenium ebenoides (A. platyneuron × Camptosorus rhizophyllus), and Dryopteris cristata × marginalis Davenport, two suspected hybrids, which occur in nature. Recently at least one more cross has been artificially produced by Mr. Amedee Hans, of Stamford, Ct., between Dryopteris Filix-mas and D. marginalis. This, however, has not yet been found wild.

Study of these three authenticated hybrids shows that they agree in general with the hybrids of some flowering plants. They are sterile, usually larger than the parents, sometimes abnormal, and in many characters intermediate to a greater or less degree between the parent species. In view of these facts, it seems reasonable to interpret as hybrids other forms (principally in Dryopteris) which are sterile and similarly intermediate between two species.

Some of these are very characteristic and might be considered separate species. At least two have been so described. This view, however, is untenable because of their sterility, and their distribution, rare or occasional with the parent species, or at least