Friesia IV, 3

-164 -
Fig. 27. Agaricus exquisitus Vitt.
Sketch drawn after V i t t a d i n i's plate (3:4).
As here interpreted, P. arvensis eannot be synonymous with Ag.
exquisitus Vitt., V i t t a d i n i's species being too thiekset for this
(see fig. 27), more reminiscent of the low-stemmed P. nivescens,
since the white colour of the cap and the white flesh (according to
V i t t ad i n i: finally faintly flavescent in the stem) and the habitat
"in ruderatis, ad latera viarum" are common characters, while P.
nivescens is not generally markedly hollow-stemmed, like A. exquisitus.
R i c k e n has called P. arvensis sens. restr. P. cretacea Fr., a
name unfit for use because P. cretacea is not a Psalliota species but
Lepiota naucina Fr. To use the name P. arvensis for a markedly
woodland species such as P. obrwptibulba, as has been done by