2 Dansk Botanisk Arkiv, Bd. 2, Nr. 7. 



The number of Plutei found in Denmark is comparatively 

 large. While Fries (in »Hymenomycetes Europæi«) does not men- 

 tion more than 15 species found in Sweden, the total number 

 of Danish species is at least 18. But this is not to be wondered 

 at, considering that the beech (Fagus) is the favorite host of 

 most species, and Denmark is particularly rich in beechwoods. 

 (Of course it must also be taken into consideration that a num- 

 ber of »new« species have been detected since the time of 

 Fries). 



Of these 18 Danish species only two (cervinus and nanus) 

 are common, and most of the others are exceedingly rare or at 

 least very sporadic. Two of the Danish species (P. roseo-albus 

 and P. leoninas) I have never met with during 25 years of in- 

 vestigation (P. roseo-albus has not been seen here for more than 

 a century!), and several others I have only found once or twice. 

 What also causes no little difficulty to the study of the Plutei 

 is their solitary occurrence: It is very rare to find a number of 

 these fungi growing together and thus to get specimens in dif- 

 ferent stages of development for comparison and figuring. Thus 

 P. umbrosus and P. phlebophorus are wanting in my collection, 

 as the specimens found by me have not been in a stage fit for 

 portraying. 



Still I have succeeded in figuring some 14 species, besides 

 some fairly distinct varieties (17 plates in all) or more than Fries 

 himself had ever seen alive. 



The Fries'ian idea: to divide the genus into groups according 

 to the texture of the cuticle of the cap, I believe in the main 

 the right one. But being confined to macroscopic investigation 

 Fries was not able to draw the boundary-lines between the 

 tribes with sufficient exactness. — Fries, it will be remembered, 

 arranged the species in three groups: the fibril 1 ose, the a torn ate 

 and the glabrous species. The microscopic examination however 

 clearly shows that there are in fact only two main types: a) the 

 species in which the cuticle is of fibrillose texture and b) those 

 in which it is granulöse, being made up of subglobular, inflated 

 cells. 



In the first group, which I shall term Tricholomatæ , the 

 cap varies from almost smooth and silky (P. pelliius) to very 

 rough, pilose or squamulose (extreme forms of P. cervinus). In 

 the other group, Micacece, the cap is sometimes covered with glit- 

 tering »meal« (P. semibulbosus), while in other cases it is smooth 



