[Vor. 3 
198 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
figures showing these points. For convenience this collection 
will be referred to below under my herbarium number, 2316. 
A microscopic examination of the hymenium of this and 
other collections of P. cervinus reveals some interesting va- 
riations in the form of the cystidia. These are more or less 
flask-shaped structures and hyaline. The accompanying fig- 
ures show the variations. In all collections examined (ex- 
cept the one referred to above) some of the eystidia have 
peeuliar thorn-like projections more or less abundant. Figure 
A is from my herbarium, No. 2809, and in most eollections 
it is probably the most typical form present. Figures В, С, 
and D are from my herbarium, No. 1624, and Ше thorny type 
ts 
A в c 
Fig. 1. Various types of eystidia found in hymenium of Pluteus 
cervinus: A, from herbarium No. 2809; B, C, and D, from herbarium 
No. 1624, the thorny type D being most abundant; E, eystidium of 
P. cervinus var. caespitosus. (This type is also present in other col- 
leetions.) F, spores of P. cervinus; G, spores of P. cervinus var 
caespitosus. 
of eystidium was better developed in that collection than in 
any other one examined. These sharp projections were most 
often not present on the apex of the cystidium, but were scat- 
tered along the sides as thorns on a stem. In both eollections 
eited and in all others examined there were present also a 
large number of entirely smooth, sharp-pointed eystidia. 
When collection No. 2316 was examined no cystidia with 
thorny projections were seen. It 15 very doubtful whether this 
is a constant character on which, together with other before- 
mentioned facts, a new species might be segregated. How- 
ever, there are certainly no such eystidia present as in the 
other collections; but the presence in other collections of en- 
