THE GENUS FOMES. 



As defined in Saccardo, the genus Fomes embraces the pileate species with 

 pores, which are perennial, forming successive strata of pores each year. In this 

 sense it is a very easily-recognized and natural collection of plants. We would 

 restrict it to this definition. Fomes are easily known, being mostly hard, woody 

 species that persist for years on trunks of trees. A few of the perennial, hard species 

 (Trametes pini and Trametes odorata as usually known) were not included in Fomes 

 because the pores were not supposed to be in strata. This is a mistake for the 

 pores ar^ in as distinct strata as any species of Fomes. We have included them as 

 Fomes species in the addendum. 



There is another section of polyporoids that might be. sought in Fomes, but 

 which is not included. These are the perennial, resupinate' species with strata of 

 pores. As these also would be included in Poria, ..taking the simplest definition of 

 this genus, viz., "resupinate Polyporus," we think it better to so classify them. A 

 plant that is usually a Poria will rarely form a pileus. We know two such in Sweden, 

 but we include them in Poria, as we feel that species should be classified according 

 to their usual form. 



In temperate regions there is usually no trouble whatever in distinguishing a 

 Fomes from a Polyporus, the Fomes being the hard, subwoody, perennial species, 

 the Polyporus the soft, fleshy, annual species, but in the tropics some species of 

 Polyporus, as Polyporus gilvus, sometimes take perennial forms. Also there are 

 species of Polyporus in the temperate regions, as Polyporus dryadeus, which when 

 old become hardened and indurated, but that does not make them Fomes. 



Although Fomes is usually such a simple and easily-recognized genus, there 

 are in our "literature" perhaps more species that are wrongly classed as Fomes 

 than of any other genus. This is due to careless work on the part of those who first 

 arranged the species, and largely to Cooke, who made the first general compilation, 

 which was followed by Saccardo. I doubt if a single one of the first sixty-one species 

 found in Saccardo belongs in the genus according to the definition that Saccardo 

 gives, but this was fully considered in our pamphlet on the Stipitate species. 



Fomes are mostly sessile plants, for naturally plants that persist for several 

 years must have a firm attachment to the host. Some species, such as Fomes ap- 

 planatus, normally sessile, may develop stipe-like bases growing under unusual 

 conditions. A few species, (cfr. Section 75) in the tropics have a natural tendency 

 to form a stipe.' The tissue or context, as it is called, of most Fomes is hard and 

 subwoody, a few species, such as Fomes Laricis, Fomes perlevis, Fomes floccosus 

 have soft, friable or spongy tissue. Where measurements are given in this pamphlet 

 as the size of a species, it is of course our intention to convey only a general idea. 



In shape, Fomes are divided into those with ungulate or hoof shapes, and 

 applanate or relatively thin shapes. The general shape is usually characteristic of 

 the species. Thus, Fomes applanatus, as its name implies, is generally flat and 

 relatively thin, but sometimes ungulate specimens occur. I think the position of 

 growth in relation to the host has something to do with it. Thus in France, where 

 I noted Fomes fomentarius growing abundantly on the standing beech trees, the 

 shape was ungulate, but when it developed on a fallen trunk I found it more thin 

 and applanate. As a usual thing, Fomes grow on standing trees, and hence are 

 usually ungulate. 



The general color of the context is the most constant feature of the species of 

 Fomes, and has been used as a basis for grouping the species in most works. The 

 color may vary a few shades in the same species, but usually the context color is 

 the best single character that a species has. In designating the color, we have 



