20 BOTANICAL GAZETTE [JULY 
their form, have contributed in no small degree to the results 
obtained. 
As is well known, the investigations of Mottier+ upon division 
of the pollen mother cells in Podophyllum, led Strasburger® to 
believe that a reducing division of the chromosomes occurred 
during the second mitosis of the pollen mother cell.. But more 
recent researches by Mottier, especially upon the condition of 
the chromosomes in the daughter nucleus and the origin of the 
chromosomes for the second division, led Strasburger® to recede 
from his former position and to reaffirm his conviction that the 
second division is the result of a longitudinal cleavage. Accord- 
ing to Mottier, the chromosomes unite in the daughter nucleus 
of the first division in such a way as to form a continuous single 
band, z.¢., a band made of single chromosomes united end to 
end, the arms of the V-shaped chromosomes and of the paired 
ones, where transverse division has taken place, open out to 
join with the arms of neighboring ones. This band forms the 
spirem, which splits longitudinally before it segments into the 
chromosomes for the second division. Asa result of this proc- 
ess of longitudinal fission of the spirem in Podophyllum, the 
segments or chromosomes are paired, but the pairs in the case 
of Podophyllum would then be the result of longitudinal fission, 
The separation of the members of the pair at the nuclear plate : 
during the second mitosis would not then be here a reducing — 
division. 
These conclusions of Strasburger and Mottier led me to ; 
study very carefully the same stage in Trillium. As I have © 
indicated above, the evidence seems to me taeShow that the 
chromosomes retain their individuality through the daughter — 
nuclei from the anaphase of the first division to the prophase of 
4MotTtier, D.M.—Beitrige zur Kenntniss der Kerntheilung in den Pollen-mut- 
si einiger Dikotylen und Monokotylen. Jahrb. f. wiss. Bot. 30: 169-204. A433 
97 
SSTRASBURGER, E.—Ueber Cytoplasmastructuren, Kern- und Zelltheilung. Jahrb. 
f. wiss. Bot. 30:375-405. 1897. 
°STRASBURGER, E. and Mortier, D, M.—Ueber den zweiten Theilungsschritt im 
Pollenmutterzellen. Ber. d. deutsch. bot. Gesells, 15 : 327-332. pl. 75. 1897. 
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