462 Massee. — A Monograph of the genus Inocybe , Karsten. 
a Fungus common to Europe and America (Fig. 11). (2) Nodulose ; this 
type of epispore marking varies considerably in different species. The 
most frequent form is where the epispore is sparsely covered with large, 
blunt warts or papillae ; in a second type the nodules are only very slightly 
raised, giving the spore a wavy outline when seen in optical section (Fig. 6) ; 
a third type has the nodules elongated into blunt finger-shaped papillae 
(Fig. 12). The cystidia are present under two forms: ventricose , having 
a pronounced swelling some distance below the apex (Fig. 8) ; fusoid , when 
more or less spindle-shaped (Fig. 10). The tips of cystidia are sometimes 
crowned with a brownish mass resembling a conglomeration of small 
crystals. This feature is by some mycologists considered as of importance, 
and finds a place in specific descriptions. This character is however 
absolutely valueless ; the accumulation is simply nothing more than 
mucilage which escapes from the interior of the cystidium after the 
deliquescence of the thin portion of wall at its apex. If the air continues 
to be moist the escaping mucilage remains liquid and numerous falling 
spores are caught, forming a dense mass at the apex of the cystidium 
(Fig. 9). On the other hand, if the air is dry when the mucilage escapes, 
it dries up and contracts into a rugged mass. When the mucilage once 
dries it is afterwards insoluble in water (Fig. 8). 
True cystidia are only met with on the surface of the gills. Their 
walls are very thick and highly refringent, and when free from colour are 
very apt to be overlooked, even when specially sought after. This difficulty 
can be overcome by running in under the cover-glass a weak solution of the 
stain called c azurblau,’ dissolved in water, and adding potassic hydrate until 
the solution assumes a clear red colour. The cystidia are the first to take 
up the stain, which gradually extends to all the tissues. This stain will be 
found of general use in the examination of Fungi. 
The margins of the gills are frequently whitish, and under a pocket- 
lens appear minutely fimbriate. This appearance is due to the presence of 
large clavate or fusoid cells, which are in some species arranged in little 
groups, when the margin of the gill is described as serrulate. 
These marginal cells are often as large as cystidia, from which they 
differ in having thin walls, and not deliquescing at the apex and exuding 
mucilaginous matter. They also differ in origin, being modified elements 
of the hymenium, basidia and paraphyses ; whereas cystidia originate from 
tramal cells, and push up between the elements of the hymenium, until 
they eventually project some distance above the level of the hymenium. 
Cystidia are sometimes spoken of as excretory organs, but in reality 
nothing definite is known as to their functions, which presumably differ in 
different genera, judging from the variety in structure presented. 
It is premature to speak of the geographical distribution of Inocybe , 
considering that out of 112 known species, 80 occur in Europe, and 36 in 
