JUN 26 1905 
No. 4. —DEVELOPMENT OF ASCUS AND SPORE FOR¬ 
MATION IN ASCOMYCETES. 1 
BY J. HORACE FAULL. 
De Bary (’63, ’84) was the first contributor to our knowledge of 
the cytology of the ascus. His investigations showed that the com¬ 
paratively young ascus was uninucleate and that it continued to be so 
until its maximum size was reached ; that three successive nuclear 
divisions followed; that simultaneously about each of the eight 
resultant nuclei there gathered a rounded mass of protoplasm 
differing from the surrounding protoplasm, the epiplasm, by its 
greater transparency, and bounded off from the latter by a delicate 
line; and finally that these spore initials acquired an exospore and 
matured at the expense of the epiplasm. 
Strasburger (’80) and Schmitz confirmed De Bary’s observations 
in a number of forms, and Gjurasin ('’93) not only did the same in 
Peziza vesiculosa Bull., but by the aid of a more modern technique 
followed with much greater minuteness the processes within the 
ascus. Gjurasin discovered that the nuclear divisions were karyo- 
kinetic, that there were well marked asters, though centrosoraes 
could not be demonstrated, that the anaphase stage was reached 
before the nuclear wall disappeared, and that the nucleolus remained 
until the daughter nuclei were formed. Of greatest interest were 
his observations on the last nuclear division. The third set, unlike 
the first two sets of spindles, was placed with the long axes at right 
angles to the long axis of the cell. The asters of this generation 
persisted much later than those of the two former. During the 
final stages of division the spindles elongated considerably, bringing 
the asters near the wall of the ascus. He figured the rays as con¬ 
tinuing in the same position as when attached to the spindles, 
• though disconnected from the nuclei and folded inwards over the 
latter like the ribs of an opened umbrella. 
Dangeard’s (’94) attention was fixed on the young ascus. He 
described the origin of the asci in Peziza vesiculosa , Borrera ciliaris, 
and some two or three other forms. The first indication of the 
1 Contributions from the Cryptogamic laboratory of Harvard university.— 
LXI. 
