96 SECTION HYGROTRAMA 



violaceous. Moreover, the pilei do not appear to have been hygro- 

 phanous nor striatulate. One feels that the specimens in the box are 

 not those originally sent to Peck by Simon Davis. 



SECTION HYGROTRAMA (Singer) stat. nov. 



Hygrotrama Singer, Sydowia 12: 221. 1958. 



Hymenophoral trama of interwoven to somewhat interwoven hy- 

 phae; epicutis of pileus an hymeniform layer of clavate to pedicellate 

 cells; clamp connections present or absent; hymenophore waxy; ba- 

 sidia hygrophoroid. 



Type species: Hygrotrama dennisianum Singer. 



The species grouped here have been the cause of more discussion 

 than any other group in the family or genus, and the end is not yet 

 in sight. Smith and Hesler ( 1954 ) objected to classifying members of 

 this group in Armillariella. Singer (1958) erected Hygrotrama as a 

 genus of the Hygrophoraceae to contain them, and we think this is cer- 

 tainly a step in the right direction. We prefer, however, to go two 

 steps farther and recognize the group at the level of a section under 

 subgenus Hygrophorus. The latter, classically, as a genus or subgenus, 

 has been subdivided into groups on single-character differences involv- 

 ing hyphal arrangement in the hymenophore. However, careful study 

 showed, and we (1942) pointed out, that the difference between 

 Camarophyllus (now Camarophyllopsis) and Hygrocybe was not very 

 sharp. This was our chief reason for refusing to recognize these two 

 groups at the generic level. Now a third group, Hygrotrama, also char- 

 acterized by a single feature, the hymeniform epicutis of the pileus in 

 which the hyphae of the hymenophoral trama are mostly intermediate 

 in arrangement between the parallel type and the interwoven type, 

 has been introduced into the discussion. In view of the intermediate 

 position of Hygrotrama and the fact that it is very clear, at least to us, 

 as to how this type of epicutis originated in the genus, the recognition 

 of genera at this level still is, to us, unjustified. The problem is just 

 what is meant by hymeniform. We do not consider that a trichoder- 

 mium of hyphae, in which the end cells are somewhat cystidioid, rep- 

 resents an hymeniform layer. Singer includes this species in Hygro- 

 trama, but we exclude it. If one looks to other genera for a comparable 

 situation as regards the epicutis of the pileus, Pluteus is the best ex- 

 ample. In this genus there are many degrees of epicuticular types from 

 appressed narrow gelatinous hyphae to the true hymeniform type. A 



