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CLASSIFICATION OP AGARICS 119 ^^<^TA 



GAU 



eut species are of all shades between sliiuiug wliite and egg-yellow, 

 and this fact alone separates them from any one of the spore-color 

 groups of the Agaricaceae. ISome authors consider the forking of the 

 gills as Avell as tlie veiuing in the interspaces of the gills important 

 diagnostic characters. 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 ob- 

 served with veined interspaces and some forked gills that this 

 character loses most of its value. In R. variata the forking is 

 dichotomous or mostly so and reaches its highest development. The 

 different lengths of the gills are, on the contrary, much more impor- 

 tant characteristics. They may be alternately long and short as in 

 the Compactae, or they may be all of one length with rarely any 

 secondary or shorter gills. Intermediate cases occur in the Sub- 

 rigidae, but even here the short gills are not numerous. Their shape 

 and width are also of value, since the anterior and posterior ends 

 have a characteristic width which accompanies other characters of 

 the given subgenera. The STrJM is usually white, sometimes red or 

 slightly ochraceous, in some species changing to ashy, etc., with age. 

 The reticulations on the surface are obscure and of no diagnostic 

 value. It is usually spongy-stuft'ed within and may become cavern- 

 ous in age or hollowed by grubs; in the Compactae, however, it is 

 usually solid. The TRAMA is composed of large bladder-like cells 

 arranged in groups and surrounded by strands of slender hyphae, 

 as in Lactarius. Such a structure is said to be vesiculose and ac- • 

 counts for the more or less brittle consistency of the plants. Since 

 the difference in this consistency is accompanied by other good 

 1 >4:-haracters, it is made the basis of a division of the genus into its 

 1 Subgenera. The TASTE as in the Lactarius, is sharply acrid in some 

 ~ Species, slowly or slightly acrid in others, and entirely mild in a 

 •^ -Considerable number. This is an important character for the identi- 

 ■^ <:fication of the species and is fairly constant. It is necessary to 

 "" ghave fresh- plants to be sure in some cases that the acridity is pres- 

 ^ ^cnt. Sometimes plants which are apparently mild will be found 

 pi ^to have a slight acridity only Avhen very young, or only in the gills 

 2 ^and not elsewhere. The ODOR of some species, e. g., R. foeffnis, R. 

 J foetantula, R. compacta, etc., is quite characteristic and should 

 never be unconsidered. One must not confuse this test by apply- 

 ing it to plants already in the first stages of decay. SPORf] 

 [•RINTS -are considered by most as the most essential means of 

 fettling the identity of closely related species. It has been claimed 

 that the color is constant and with this claim I agree. It is also- 

 '**8^ 2— Rus. 



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