302 BOTANICAL GAZETTE [OCTOBER 
ment of the hyphae composing that part ceases. The cells between 
the cortex and hymenium, however, remain active and add to the ” 
cortex and to the hyphae which produce paraphyses. 
The ascogenous hyphae are large and branch profusely. At the 
ends of these are formed typical hooks, consisting of binucleate 
penultimate and uninucleate ultimate and antepenultimate cells. 
The two nuclei of a penultimate cell may fuse to form the nucleus 
of an ascus, or they may divide and give rise to the four nuclei of 
another hook. The uninucleate ultimate cell usually grows down 
and fuses with the antepenultimate cell, after which the two nuclei 
may give rise to the nuclei of another hook, or they may fuse to 
form an ascus. 
When the hymenium is first formed, it is covered by the younger 
setae of the cortex, but as its diameter is increased and its level 
. raised by the multiplication of the number of asci and paraphyses, 
it comes to be exposed. 
No fusion of nuclei was Sceroed in either the ascogonium or 
ascogenous hyphae, except where two nuclei fuse to form the pri- 
mary nucleus of an ascus. 
The nuclei of the ascogonium and ascogenous hyphae appear to 
be entirely similar except for size, and the same number of chromo- 
somes, five, persists throughout their divisions. When the chromo- 
somes are first formed, they are frequently grouped in a mass 
resembling a second nucleolus. The chromosomes become con- 
nected with a centrosome which was not apparent during the 
resting stage. This centrosome divides, and the two daughter 
centrosomes come to be situated at the poles of the spindle. At 
metaphase the five chromosomes divide, and at anaphase five pass 
to each pole. The daughter nuclei are usually organized at some 
distance from each other, but sometimes they are so close together 
that they resemble fusing nuclei. 
The first division in the ascus is heterotypic. Synizesis is pro- 
duced by the contraction of a single spireme. After synizesis the 
spireme splits longitudinally. The two halves come together again, 
after which the spireme contracts considerably and segments into 
five elongated chromosomes. A centrosome makes its appearance 
on the nuclear membrane and becomes connected with the chromo- 
