NOTES. 
ON THE REDUCTION OE THE CHROMOSOMES IN THE 
NUCLEI OF PLANTS. — Since the classical researches of Van 
Beneden on the development of the sexual cells and on the process of 
fertilisation in As car is megalocephala, which date from the year 1883, 
few points have been more studied than the reduction of the chromo- 
somes (chromatin-segments), which is an essential feature in the 
development of the sexual cells, with the ultimate object of arriving at 
the physiological significance of this curious and interesting phe- 
nomenon. 
Although the researches into this matter which have been made by 
botanists have hardly met with the attention which they deserve, it 
seems that it is by the study of these phenomena in plants that the 
next advances toward the solution of the problem are to be made. 
Already in the year following Van Beneden’s first publication, it was 
shown by Guignard 1 and by Strasburger 2 that a reduction in the 
number of the chromosomes takes place in connection with the 
development of the reproductive cells of Angiosperms. Taking first 
the development of the asexual reproductive cells, the microspores 
(pollen-grains) and the macrospores (embryo-sacs) of these plants, it is 
conclusively proved that here a reduction in the number of the nuclear 
chromosomes takes place. Guignard 3 has ascertained that the nuclei 
of the mother-cells of the pollen in Lilium Marlagon each contain 
only twelve chromosomes, whilst the nuclei of their immediate arche- 
sporial ancestors each contain twenty-four; and that similarly, the 
nuclei of the corresponding cells in species of Allium contain re- 
1 L. Guignard, Nouvelles Recherches sur le Noyau Cellulaire, Ann. d. sci. nat., 
Bot., ser. 6, t. XX. 
2 E. Strasburger, Neue Untersuchungen ueber den Befruchtungsvorgang bei den 
Phanerogamen. 
3 Comptes Rendus, t. CXII, 1891, p. 1074-76; also Nouvelles Etudes sur la 
Fecondation, Ann. d. sci. nat, Bot., ser. 7, t. XIV. 
