304 DIVISION IT.—COURSE OF DEVELOPMENT OF FUNGI. 
Their shape and size vary in the different species; they are usually constant and 
characteristic in each species, less so in genera and subgenera. The large, ellipsoid 
or elongated, obtuse vesicles of the Coprini, which strike the naked eye, are remarkable 
forms which require to be especially mentioned (Fig. 139). In a number of other 
species they are cylindrical, club-shaped or flask-shaped, blunt at the extremities in 
Polyporus umbellatus according to Corda, and in Agaricus viscidus, L. according to 
Phoebus, or pointed, or with a knob in Lactarius, Russula, and Boletus according to 
Corda; Agaricus fumosus, P. and A. laccatus, Scop. &c. have simple or branched 
cylindrically hair-shaped cystidia according to Hoffmann; in A. Pluteus, P. they are 
flask-shaped and furnished at the upper extremity with several short sharp projections 
which are bent a little backwards into the shape of a hook!. In most of the 
leathery or woody species in which they occur they are narrowly conical in form with 
sharply pointed extremities which stand out prominently ‘like lance-points’ from 
the hymenium, as in Stereum, species of Corticium, Trametes Pini, Polyporus 
igniarius, &c. 
The structure of the cystidia is as follows. In the species with a juicy flesh 
a thin and usually colourless membrane encloses the colourless cell-contents which 
are either protoplasm with vacuoles or quite transparent. I found in cystidia from 
half-matured hymenia of Coprinus micaceus (Fig. 139 2) a central irregularly elongate 
protoplasmic body, from which numerous branched anastomosing threads with active 
amoeboid movement radiated to the wall; older cystidia in the Coprini are almost 
perfectly transparent. In Lactarius deliciosus and allied species the cystidia are filled 
with densely granular opaque contents. In this respect they resemble the laticiferous 
tubes, and in thick sections it often looks as though they were branches of these 
tubes, especially as they extend in this species far below the subhymenial tissue into 
the interior of the trama. But I always observed that they sprang as branches from 
non-laticiferous hyphae of the trama. The cystidia are of a deep purple-red colour in 
Agaricus balaninus, Berk.? In the conical cystidia of the non-fleshy species the 
membrane, especially in the projecting extremities, is strongly thickened and coloured 
to correspond with the rest of the tissues. 
Further details will be found in special works on the Hymenomycetes, especially 
those of Corda, and in a separate work on the cystidia by H. Hoffmann, and in R. 
Hartig’s writings. 
According to Corda and the doubtful statements of earlier observers, the cystidia of 
the fleshy Fungi discharge their contents in the form of drops through the apex which 
is open in the figure. Neither I nor Hoffmann nor Brefeld were able to satisfy 
ourselves that this was done spontaneously ; it was but rarely that I saw the cystidia 
burst when placed in water, and according to Hoffmann this takes place quite 
irregularly. The moist surface, which often bears small drops of liquid, is a phe- 
nomenon which it has in common with all free Fungus-cells that are rich in cell-sap. 
It is plain that the formations above described in the non-fleshy forms belong to the 
same category as those in the fleshy ones, for there is no other more general difference 
between them than that between fleshy and non-fleshy species. It is as little to be 
disputed that the cystidia belong morphologically to the category of hair-formations, 
one may say indeed that they are prominent hymenial hairs. 

! Ditmar, in Sturm D. fl. III, 1, t. 28. 
? Montagne, Esquisse org. et phys. de la classe des Champignons. 
