614 Btiller .— The Function and Fate of the 
The distribution of cystidia among species and genera is very irregular. 
Thus for instance, in the Thelephoreae, whilst cystidia are present in the 
genera Peniophora and Hymenochaete , they are absent in Corticiuni , 
Stereum , Coniophora , and CraUrellus} But in a single genus some species 
may possess cystidia, and others not. Thus Psathyra spadiceo-grisea 2 and 
Pomes nigricans 3 are provided with cystidia, whereas Psathyra nolitangere 4 
and Fomes annosns 5 are without them. Even in closely allied species 
which have cystidia, the distribution of these structures may differ consider¬ 
ably. Thus in Coprinus comatus the cystidia are restricted to the free 
margins of the gills, whilst in C. atramentarins they are not only present 
in these situations but project in large numbers from the general hymenial 
surfaces. Cystidia occur in species of the Hymenogastrineae, 6 but, so far 
as I am aware, they have not been found in any other group of Gastromycetes. 
Brefeld 7 occasionally found cystidia bearing sterigmata and spores in 
Coprinus stercorarius , and he also noticed that the cystidia alternated with 
the paraphyses like the basidia. He drew the conclusion that the cystidia 
are metamorphosed basidia. In support of this view may be mentioned the 
fact that the cystidia on the basidia-free gill-margins of Coprinus comatus 
are distributed among the paraphyses in precisely the same manner as the 
basidia on the general gill-surfaces. 8 
The different types of cystidia are so diverse in size, structure, and 
distribution that it seems certain that they cannot all have the same func¬ 
tion. Cystidia are analogous to the epidermal hairs of the higher plants, 
and probably like these they perform various functions for which they are 
fitted by their peculiar structure. So far, however, comprehensive physio¬ 
logical studies of these functions have not been made, so that we are still 
almost entirely in the dark as to what they are and what part they play in 
the fruit-body economy. 
A few decades ago it was thought that cystidia were male organs. 
This view was held by Corda, Hoffmann, 9 and Worthington Smith. 10 The 
last-named writer thought that the cystidia were antheridia which produced 
spermatozoa. He believed that the spermatozoa found their way to the 
spores with which they fused, thus bringing about their fertilization. 
Earlier writers, Corda and others, stated that the cystidia of fleshy Fungi 
discharge their contents through their apices in the form of drops, but 
1 Engler unci Prantl, 1 . c., pp. 117 and 118. 
2 O. Brefeld, Untersuchungen, Heft 8, p. 47. 
G. Massee, British Fungus-Flora, vol. i, p. 221. 
4 O. Brefeld, 1 . c , p. 48. 5 Ibid., p. 161. 
6 Engler und Prantl, 1 . c., p. 297, also Fig. 150 E. 
7 O. Brefeld, Untersuchungen, Heft 3, p. 54. 
8 A. H. R. Buller, Researches on Fungi, London, 1909, PI. Ill, Fig. 13. 
9 II. Hoffmann, Die Pollinarien und Spermatien von Agaricus. Bot. Zeit., Bd. xiv, pp. 137-8, 
1 5 63. 
10 W. Smith, Reproduction in Coprinus radiatus. Grevillea, vol. iv, 1S75-6, pp. 53-63. 
