Gilbert—Cytological Studies of Lower Basidiomycetes 389 
cetes and these spores are quite comparable in this respect with 
the spores described by Fitzpatrick (11, 12) and Bensande (4). 
The spores may remain in this unicellular condition, but usually, 
if moisture be present, will proceed to the formation of eight- 
celled spores (figs. 2-8). 
It is very possible to find all stages in this process in a single 
mount, and the details are readily observable. The primary 
nucleus divides, the two nuclei separate, and a cross wall is soon 
laid down, giving rise to a two-celled spore. Repeated nuclear 
division with consequent formation of cross walls, during a 
period varying from four to eight hours, will then result in the 
final eight-celled spore (figs. 7, 8). 
I have spoken of the one-celled spore as mature, but it is ques¬ 
tionable which of the described stages is that of a mature spore, 
as spores in any of these stages will remain viable for several 
days when exposed to the ordinary laboratory conditions. 
The nucleus of the spore contains a single nucleole and an 
abundance of heavily staining chromatin. In division the typi¬ 
cal fungal spindle is formed with its very plastic chromosomes. 
Because of this plasticity it is not an easy matter to make accur¬ 
ate counts of the chromosomes, but from the studies made the 
chromosomes seem to number three or four as noted on the spin¬ 
dle. The nucleole is soon crowded to one side and very quickly 
breaks down. Centrosomes are present in connection with all 
the nuclear divisions within the spore. Astral rays are at times 
to be noted (fig. 3), but they are so few in number and so deli¬ 
cate that they are easily overlooked. 
Mycelium 
The spores as a general rule do not produce hyphae until the 
eight-celled stage has been reached, but many instances of the 
production of hyphae by four-celled spores have been noted. 
Text figure 1 shows such a four-celled spore with a portion of 
the mycelium developed from it. This was taken from a wood 
decoction where there was continued growth of hyphae for thir¬ 
teen days, and the spore with mycelium was taken out at the 
end of twenty-one days, killed, and stained. The cells of the 
various hyphae were found to have one and only one nucleus 
each. There were very few anastomoses, but seemingly no 
migration of nuclei during this entire period. 
