358 THE BASIDIOMYCETES 



margin of the pileus to the stipe is the inner veil or partial veil. 

 Since it mav not increase by the addition or formation of new 

 hvphal elements, it may escape detection when the pileus ex- 

 pands to the extent of exposing the gills to the exterior. On the 

 other hand, the partial veil mav be reinforced to such an extent 

 that, when the pileus expands, it will remain as an annulus, mov- 

 able or not, surrounding the stipe, or as a frayed cortina hanging 

 from the edge of the pileus, or both annulus and cortina may 

 exist. The annulus becomes well developed in Amanita, Armil- 

 laria, Coprinus, Lepiota and Psalliota, and in Cortinarius arach- 

 noid cortinae exist at the lower edge of freshly expanded pilei. 



Quite a distinct additional structure occurs in Amanita and 

 Amanitopsis. Surrounding the entire outer surface of the young 

 button, like an eg^g- shell, is a membranaceous layer, the universal 

 veil. As the pileus expands, this shell ruptures circumscissilely, 

 and its remnants may then be seen as scales at the upper surface of 

 the pileus and as a cup-like sheath or volva around the base of the 

 bulbous stipe. The partial veil in Amanita is also strongly devel- 

 oped and may grow as the pileus expands, eventually tearing at 

 the rim of the pileus; it then hangs skirt-like around the stipe. 



The universal veil has been demonstrated as an external layer 

 around the primordia of Agariciis arveneis, A. campestris, A. 

 comtuluSy and Amanitopsis vaginata [Atkinson (1914)]. 



Classification. In classifying asrarics it is essential first of all 

 to divide them into wholly artificial tribes, the groupings being 

 based upon color of the spores, as follows: (1) Leucosporae, 

 spores hyaline; (2) Rhodosporae, spores pink to red; (3) Ochro- 

 sporae, spores yellow to ochre; (4) Alelanosporae, spores dark 

 brown, purple, or black. Manifestly the use of spore color as a 

 primary basis of division results in separating similar genera into 

 different tribes. If spore color cannot be determined by direct 

 examination, a spore print should be made. 



The characters next employed in distinguishing genera in- 

 clude: (1) shape of the pileus; (2) consistency and character of 

 the stipe and its attachment to the pileus; (3) shape, arrangement, 

 and attachment of the gills; (4) presence or absence of annulus, 

 cortina, and volva; (5) nature of the pilear surface and stipe and 

 their markings. With experience genera soon come to be satis- 

 factorily recognized, but specific distinctions are much more 

 difficult. Size and color of the fructifications, size and markings 



