THE ANATOMY OF A MUSHROOM. 
395 
membrane is scarcely accurate, since it is composed of the apical 
cells of the threads which together constitute the hymenophore. 
It might be possible to isolate a thread from the m}^celium, to 
trace it up the stem, through the pileus, down one of the gills 
to the surface, and there to support one of the basidia, with its 
four spores. During the course of such a thread the cells would 
be modified, sometimes elongated, sometimes shortened, and at 
length when reaching the hymenium, in some species, spherical, 
continually giving off lateral branches, and interlacing with the 
neighbouring threads, but maintaining a continuity through the 
whole structure, so that typically the whole mushroom may be 
regarded as a congeries of branched threads, bearing spores at 
their tips, consolidated together into one individual. 
Basidia, or formative cells, are usually expanded upwards, so 
as to have more or less of a clavate form, surmounted by four 
slender points or tubular processes, each supporting a spore, 
(fig. 5 6). The contents of these cells are granular, mixed ap- 
parently with oleaginous particles, which communicate through 
the slender tubes of the sporophores, or sterigmata, with the in- 
terior of the spores. Corda states that although only one spore is 
produced at a time on each sporophore, when this falls away others 
are produced in succession, for a limited period. On this point 
we have no additional evidence. As the spores approach matu- 
rity the connection between their contents and the contents of 
the basidia diminish and ultimately cease. When the basidium 
which bears mature spores is still well charged with granular 
matter, it may be presumed that the production of a second or 
third series of spores is quite possible. Basidia which are 
wholly exhausted of their granular contents, and become hyaline, 
may often be observed. Seynes*^ observes on this subject, If 
we could assure ourselves that amongst the tetrasporous basidia 
there are but two generations, each of four spores, that would 
show another affinity with the theca3 of the Ascomycetes, which 
produce, for the most part, eight spores.” 
Cystidia are usually larger than basidia, varying in size and 
form in different species. They present the appearance of large 
sterile cells, attenuated upwards, sometimes into a slender neck 
(fig. 5 c). Corda was of opinion that these were male organs, and 
gave them the name oipollenaire. Hoffmann f has also described 
both these organs under the names of jpollinaria and speiinatia ; 
but he does not appear to recognise in them the sexual elements 
which those names would indicate, whilst Seynes recognises 
* “ Essai (Time Flore mycologiqiie de la nigion de Montpellier et du Gard,” 
par J. de Seynes. Paris, 1863. 
t Die Pollinarien iind Spermatien von AgaHcus in Botanisclie Zeitimg,” 
29 Febr., 7 Mar. 1856. 
