MIDDLETOX FUNGI. — GATES. 121 



Sclerotia are similar brownish bodies formed on tlie mycelium 

 for the purpjse of resisting the effects of dry conditions. Gener- 

 ally, however, the vegetative mycelium consists merely of 

 irregalarlj' branching septate hyphas, which in parasitic species 

 send haustoria into the living cells of the host, and absorb their 

 contents. Tiius the mvcelium afiords verj^ few characters for 

 determination, and in the present state of our knowledge very 

 few species can be recognized from their mycelia. 



Another diffi3ulty of determination is the great amount of 

 variation frequently found within a species, making it almost 

 impossible to accurately determine its limits. The color, size 

 and shape of almost any part of the hymenophore may vary, so 

 that the plant may be recognizable only hy its general habit 

 and by certain distinctive, though evanescent characters scarcely 

 describable in words. Hence the great value of photographs, 

 drawings and water colours as an aid to determination. 



As has already been mentioned, the mycological flora of 

 Canada is comparatively little known, and as new species are 

 continually being discovered in the United States and Europe 

 where the greatest amount of work has been done, we may look 

 forward to a rich harvest for future Canadian nwcolotyists. 



Much is being done in the United States to popularize this 

 subject by the formation of mycological clubs, some of which are 

 specially devoted to the discovery and testing of the numerous 

 and valuable edible species, and the publication of bulletin.s. 

 Among popular books on the subject ma}^ be mentioned 

 Atkinson's " Mushrooms, Edible, Poisonous, etc.", published by 

 Andrus & Church, Ithaca, N. Y., at S3.00, and Marshall's 

 " Mjshroom Book " obtainable from Wm. Briggs, Toronto, f"r 

 33.00. These are splendidly illustrated with photographs, and 

 will serve as the best basis for the beginner. Numerous other 

 works, some of them in several volumes, are available for 

 students wishing to pursue the subjecr in greater detail. Among 

 these authors may be mentioned, Mcllvaine (one large volume), 

 at So. 00, Massee (four volumes), Stevenson (two volumes), and 

 Saccardo (fifteen volumes). 



