74 REPOET OF THE COMMISSIONER OF AGRICULTURE. 



Eight sets of plant duplicates are now being prepared as rapidly as pos- 

 sible for fnitlier distribution, a part to colleges in this country, and a 

 part for foreign institutions. The duplicate wood sections are also being 

 prepared for distribution. 



Of the very large contributions which were made to the United States 

 by foreign governments represented at Philadelphia, a considerable por- 

 tion conies to this Department, and will serve not only to greatly enrich 

 our Museum and Herbarium, but there are quantities of some of these 

 objects in duplicates, which, it is understood, are to be divided and pre- 

 pared for distribution to various museums and institutions of learning 

 in this country. This will involve a large amount of work for this 

 division, but the benefits to be conferred upon the cause of education 

 through this means will be well worthy of the labor and expense. 



As a result of the centennial collection of forest-trees, much informa 

 tion has been gained respecting species hitherto imperfectly known, and 

 several species have been obtained which were before unknown to our 

 flora, the particulars of which are given in the Catalogue of the For- 

 est-Trees of the United States, which was published by this Depart- 

 ment to accompany and illustrate the collection. 



The Herbarium has also been greatly enriched by collections of plants 

 made in connection with the procuring of the forest-tree specimens, and 

 also by the purchase of a large number of rare and new species of the 

 Sierra Nevada Mountain region. 

 Eespectfally, 



GEO. VASEY, Botanist. 



Hon. Frederick Watts, Commissioner. 



MICROSCOPIC INVESTIGATION. 



By Thomas Taylor, Microscopist. 



During the past year a large portion of my time was devoted to the 

 preparation of a series of water-color drawings for the Centennial Ex- 

 hibition, having in view, to a limited extent, the illustration of objects 

 connected with the usual work of the Microscopic Division, a large pro- 

 portion of which represents the leading types of the genera of micro- 

 scopic fungi. Another section of the exhibit presents the results of 

 original investigations upon chemical tests for flax, cotton, ramie, silk, 

 wool, hair, and both animal and vegetable cellulose ; and still another 

 series illustrating the principal vegetable starches, to the number of 

 about one hundred varieties. These drawings present highly magnified 

 views of these microscopic objects, including those most important in 

 economic mycology, especially the fungi commonly known as molds, so 

 destructive to vegetation. The edible and poisonous mushrooms are 

 distinguished in one class of these drawings. 



MUSHROOMS. 



The importance of the mushroom as an article of diet has never been 

 properly understood in the United States, nor is it generally known how 

 abundant our supply of edible mushrooms is. Many of those popularly 

 supposed to be poisonous are not merely innoxious, but highly nutri- 

 tious, containing as they do many of the elements of animal food. 



In France, Germany, and Italy the mushroom forms so important a 

 part of the food of the people that one distinguished writer has spoken 



