LEVINE: CYTOLOGY OF HYMENOMYCETES 161 
Centrosomes and astral rays are strongly and typically developed. 
Although it is difficult to determine the exact number of chromo- 
somes certainly more than two are found at all stages. In the 
first division of the basidium where the spindles are large as many 
as six to eight can be counted. 
Aberrant types of basidia have been found in Boletus chrysen- 
teron, B. punctipes, and B. griseus. The abnormality consists in 
the appearance of mature sterigma-like projections while the 
nuclei are still in the process of division. FIG. 77, PL. 5, shows a 
basidium with one of its four sterigmata well developed. The 
division figures are perfectly normal, with the exception that they 
are almost perpendicular to the transverse axis of the basidium. 
THEORETICAL DISCUSSION 
I cannot agree with Knoll that the cystidia in the Basidio- 
mycetes are hydathodes. The cystidia of the Boleti I have studied 
are evidently modified basidia whose function is in some sense 
glandular. The quantity of material excreted is very large and 
in no way resembles the mucilaginous substance found about the 
trama cells. Just how this substance is excreted by the cystidia 
is not clear but in all probability it is formed just beneath the 
cuticle as described by Tschirch (1889) for the gland cells in the 
higher plants. 
As I have pointed out, the excretion products in the form of a 
gelatinous substance may be usually found covering the entire sur- 
face of the cell. In the case of Boletus granulatus, where several 
cystidia are found together, a cushion-like gelatinous mass is 
formed. These masses are the ‘‘granules’’ (PL. 7, FIG. 12) at the 
mouths of the pores. Knoll admits that a mucilaginous substance 
accumulates on the upper part of the cystidia of Psathyrella graci- 
lis, Galera tenera, G. tenuissima, Peniophora globulosa, Paneolus 
helvolus, and Coprinus lagopus and figures the cystidia of Collybia 
esculenta, Psathyrella consimilis, and Inocybe trechispora as 
entirely covered with it. Knoll has done nothing to disprove the 
contention of Lepeschkin (1906) who showed that the discharge 
of water from hyphal cells in general depends only upon the 
condition of the plasma membrane. Biffen (1899) finds that in 
the case of Collybia velutipes, watery drops may be exuded from 
