58 ELEVENTH REPORT. 



and even in the mature forms of many of the firm species one can find the 

 striations sufficiently often to cause misunderstandings. Some authors 

 consider the Forking of the gills an important diagnostic character, as 

 well as the veining in the 'interspaces of the gills. These two characters are 

 intimately related and forking is for the most part merely a pronounced 

 development of veining. In fact such a large number of species have been 

 observed with veined interspaces and slightly forked gills, especially towards 

 the base, that this character loses most of its value. There are only a small 

 number where the forked gills are important, and even here the effort to use 

 this character has led to endless confusion. The Reticulations on the 

 surface of the stem have been reported as marked enough to aid in dis- 

 tinguishing a few species, but I have never seen any which were well de- 

 veloped throughout a single species; usually the reticulations are obscure, 

 and in this condition are often present. 



It is difficulty in fact, to obtain sufficient describable characters for the 

 separation of the large number of species in this genus. There has been a 

 tendency* to discredit the value of the acrid or peppery Taste which is used 

 by some as a useful character; yet this is still to my mind a most useful and 

 constant character. It is doubtless true that some species show a variation 

 in this respect in old and young plants, or in old decaying parts of plants, 

 but for the most part such variation is accidental, and, it is likely, that 

 where there is marked inconsistancy in this respect in one species, two species 

 are really dealt with. Distinction should be made between acrid and peppery, 

 but the data on this point are hard to get, and not everybody can make the 

 distinction easily. The Odor also is often strong enough to be used to good 

 advantage for the recognition of some species. The most important, however, 

 of the characters are those afforded by the gills. They may be alternately 

 long and short as in the first group, or they may be all of one length with 

 hardly any shorter or secondary ones. Intermediate cases occur in the 

 subgenus rigidae, but even here the short gills are not very numerous. 

 Their distance from each other and their shape and width are also of some 

 value, since the anterior and posterior ends have a characteristic width 

 relative to each other for each species. The Color of the ripe Spores, also 

 shown by the gills, are believed by most authors to be very constant, and 

 hence a spore-print of mature plants is one of the essential things to be 

 obtained in the study of these plants. Finally, one of the most valuable 

 characters is the relative Consistency of different species. The fragile 

 forms are usually easily distinguishable from the firm and compact species, 

 and this seems of svifficient fundamental importance to be used as a natural 

 character for the separation of the subgenera. It is thus seen from the 

 brief review given above that the genus is difficult, and will only yield to 

 patient and persistent effort on the part of the student. 



Because of the rather uniform changes which take place in the individuals 

 of each species while being dried, it is often possible to verify one's identifica- 

 tion by comparison of dried specimens of the same species as suggested by 

 Denniston.* This method cannot be used to any extent on the dried gills, 

 hence spore-prints are indispensable. 



The Russulas do not lend themselves well to Photographic reproduction. 

 The color, which is so characteristic, can not be caught, and the short stem 

 and broad cap prevent arrangements to show on the picture what ought to 

 be shown. 



*Dennistoii: Trans. Wis. Acad. Sci. etc , 1905: Barbier: Bull Soc. Mycol. de France 1908. Vol. 

 XXIV, P. 230. 



