458 BOTANICAL GAZETTE [DECEMBER 
observed that there are at first two nuclei in the recurved tip of an 
ascogenous hypha, which divide simultaneously by mitosis, thus 
forming four. One of each pair of nuclei enters the young ascus, 
which arises as an outgrowth of the penultimate cell. These two 
nuclei, which in this case are thus shown to be not sister nuclei, fuse 
to form the ascus nucleus. In a study of spore formation HARPER 
determined and fully described the process involved in the delimitation 
of the spores. Each nucleus forms a beak which is connected with 
a persistent central body, bearing at its outer end the astral rays. 
These rays bend backward and downward, finally coming in contact 
laterally and fusing to form a thin membrane, which continues to 
grow backward until a focal point is reached, thus completing the 
process of spore delimitation. This kinoplasmic membrane cuts the 
spore out of a homogeneous mass of protoplasm. He has described 
this process in Erysiphe communis, Peziza vesiculosa, Ascobolus jur- 
juraceus, Lachnea scutellata, Pyronema confluens, and Phyllactinia 
corylea. 
BERLESE (’99) has studied spore formation in Tuber brumale, 
concluding that the plasma membrane of the spore is formed from the 
astral rays. His results on nuclear phenomena agree essentially 
with those of GJURASIN and HarPER. MArreE (:03, :04, :05) has 
described the nuclear divisions and ascus formation in Galactinia 
succosa and several other Ascomycetes, and confirms the method of 
spore formation as described by HARPER. 
GUILLIERMOND (:03, :04, :05) studied several species with especial 
reference to karyokinetic division, the structure of the epiplasm, and 
the formation of the asci. He confirms the results of Marre on 
Galactinia succosa, finding that the tips of the ascogenous hyphae 
are not recurved, but that the terminal cells give rise to the asci. 
Wherever spore delimitation was studied it was found to follow the 
method described by Harper. 
BARKER (:03, :04) in a preliminary study of Ryparobius, a form 
whose asci contain more than eight spores, finds that the asci are 
formed from the penultimate cells of the ascogenous hyphae which 
contain two nuclei, these subsequently fusing to form the ascus 
nucleus. He also studied the nuclear divisions and spore formation. 
Sixty-four free nuclei are formed, which become regularly grouped 
