MIDDLETOX FUNGI.— GATES. 119 



attention of any one than aiding in the determination of the best 

 means of combatting these parasitic fungi, which are destroj'ing 

 thousands of dollars wortli of timber annually'. This cannot be 

 accomplished without a study of the life-history of these plants, 

 their manner of entrance and the stages of their development in 

 the tissues of the tree. 



Perhaps a certain feeling of revolt at being engaged in col- 

 lecting Toadstools and Putfballs, as they are commonly called, 

 nearly all of which are generally regarded as poisonous, has 

 deterred some from becoming mycologists. But after the first 

 introduction to this enticing field of work the interest o-rows 

 apace. The distinctions between species are often extremely 

 perplexing, and perhaps there is no better training in keenness 

 of observation than the determination of fungi. The great 

 mycologist Fries has remarked that species often appear to be 

 grouped around other species as satellites, and the various grada- 

 tions of relationship which seem apparent on examination of 

 closely similar species, is often striking. 



The main characters made use of in the determination of 

 species of Hymenomycetes are the size and shape of the fructi- 

 fication or hj'menophore, and the particular characters of its 

 parts. Some of these characters are the flesh}^, fibrous or 

 cartilaginous structure of the stem, whether hollow, solid, framle, 

 compact, spongy, etc. ; of the cap or pileus, the color and shape-, 

 whether viscid, glutinous or dry, with or without a pellicle, 

 squamulose, warty, areolate, hairy, tomentose, smootli, etc. ; of 

 the gills in the Agaricacea^, whether adnate to stem, adnexed, 

 free or decurrent, broad or narrow, etc. The presence or absence 

 of an annulus on the stem, and a volva or veil, are also import- 

 ant generic characters. The gills of the agarics are replaced in 

 Polyporacea3 b}^ pores, in Hydnacese by spines, in the Thele- 

 phoracea? and Clavariaccfe by a smooth hymenium or spore- 

 bearing surface. 



The trama, or interior portion of the gills, exhibits one of 

 two characteristic appearances in cro.ss section under the micro- 

 scope. In most genera the trama is floccose, consisting entirely 



