matched it in Ridgway's Standard and used his terms. Wherever a definite color 

 term is used in this work, as "Sudan Brown," the term is taken from Ridgway. 

 Due allowance, however, must be made for slight difference in color of specimens, 

 which may vary through two or three shades of Ridgway, and particularly for my 

 personal error, for I am not expert at matching colors. The use of definite color 

 terms will be nearer the truth, even if not strictly accurate, than the prevailing 

 custom of employing such terms as "brown," "ferrugineous," etc. The larger part 

 of the species of Fomes have context color of some shade of brown. For conveni- 

 ence, we have endeavored to arrange them into light brown and dark brown sub- 

 sections, but too much dependence must not be placed on it, for I doubt if the line 

 of division is definite enough to be practical. 



The use of the microscope in the determinations of species and relations of 

 species to each other is a recent introduction. The older mycologists judged 

 species only on their general resemblance, and they were often badly mistaken. 

 The microscope shows some marked and constant characters, as the color and shape 

 of the spores, the presence or absence of setae on the hymenium, and in a few instances 

 special structural characters, as the large, colored, bristle-like hyphae imbedded in 

 the tissue of Fomes pachyphloeus (see page 261, figure 600). 



The spores are mostly hyaline, but many species, usually with brown tissue, 

 have colored spores, and those of the section Ganodermus have the peculiar, trun- 

 cate spores of this section. Species with colored spores nearly always retain their 

 spores in abundance in the dried specimen. It is often difficult to find spores in 

 dried specimens of species with hyaline spores, and errors are liable to be made in 

 examining them. The spore records of this pamphlet are as I have found them, 

 excepting in a few instances. The size of the spores as recorded is not intended as 

 absolute, for spores vary in size on the same slide. I usually pick out a spore that 

 I think is perfect and of the largest size and measure it. 



This pamphlet was written at Kew, and when I was unable to find spores, 

 Miss Wakefield, who is more expert with the microscope than I, kindly hunted for 

 them and sometimes found them, and such are recorded on her observations and 

 marked (W.). In a few cases, marked (B.), the measurements are taken from 

 Bresadola's record. 



The presence or absence of colored setae on the hymenium is a strong, though 

 I think not invariable, character of species, but, like all classes of fungi, it is re- 

 stricted to those with brown context. As a usual thing setae are easily found in 

 those species that have setae, but cases have been observed that throw doubt on its 

 being an invariable character. There are a few species, such as Fomes connatus, 

 that have large hyaline "cystidia" on the hymenium. 



Basidia are rarely if ever found in the dried specimen, but some species have 

 a sub-hymenial layer that persists and may be mistaken for spores. This latter is 

 shown in figure 600, page 261. In many species, how r ever, no indication of this 

 structure can be found. The spores as found in Fomes specimens are supposed 

 to be basidial spores, and in most cases no doubt are. Conidial spores, or spores 

 borne direct on the hyphae, are known in some species, and I suspect occur more 

 frequently than supposed, for it is difficult for me to believe that the masses of spores 

 found lining the tubes of some colored spore species are of basidial origin. 



The Fomes of Europe and the United States are well known, and probably 

 all species have been named. Also I feel sure, from the elaborate collections in the 

 New York Botanical Gardens from tropical America, very few additional will ever 

 be found from this region. The remainder of the world, particularly Australia, 

 Africa, Japan is but scantily represented in the museums, and many will yet be 

 added from these little-worked regions. Still I think all the common species of the 

 world are named. 



In preparing this pamphlet I have w r orked over the specimens in the principal 

 museums of Europe and this country, including the fine collection in the New York 

 Botanical Gardens, where is preserved the best collection of tropical American 

 material in existence. In our own museum we have as many specimens in numbers, 

 if not in variety, as are found in the other museums we have visited. Where spec- 

 imens are cited, we refer to those in our museum. We extend our thanks to those 

 who have aided us with specimens, and for the courtesies we have received in the 

 various museums. This pamphlet was written at Kew, where the most of the his- 

 torical specimens are preserved. 



