84 BOTANICAL GAZETTE [AvGUST 
Four microspores (figs. 18, zg) are usually produced from 
each spore-mother-cell, but occasionally five, six, and even eight 
are formed (figs. 20-27). Miss Lyon? also found this pecul- 
iarity in Euphorbia corollata, which in the case of Hemerocallis 
has been known for some time. The extra nuclei were fist 
described as being produced by one or more of the four tetrad 
nuclei dividing by karyokinesis. Recently, however, they have 
been described by Juel+ as being formed from chromosome 
which became isolated in one of the divisions of the spore 
mother-cell. Many tetrads having supernumerary nuclei wert 
examined, only a few of which seemed to show definitely how the 
extra number of nuclei might have arisen. In all cases whet | 
the origin was indicated by spindles or otherwise they seemed 
to have been produced by a subsequent karyokinesis. The extra 
nuclei in figs. 20 and 27 may be a result either of the indirect 
division of one of the cells of the tetrad, or of the threefold 
division of one of the nuclei at the second division. The 
division of one nucleus into three or more is quite common 
animal cells in case of pathological tissue. Wilson,’ in speaking. 
of cases of pathological mitosis, says: 
The abnormal forms of mitoses are arranged by Hanseman in two aft 
eral groups, as follows: (1) asymmetrical mitoses, in which the chromosom® 
is formed. .:. ... Lustig and Galeotti (’93) showed that the unequal 
ution of chromatin is correlated with and probably caused by aoe 
inequality in the centrosomes, which causes an asymmetrical developme™ 
the amphiaster. a 
The same author refers to the discovery of Galeott! 
asymmetrical mitoses may be artificially produced in the 
thelial cells of salamanders by treatment with various @ 
Guignard?® finds very irregular and also multipolar spindles sale 
3 A contribution to the life history of Euphorbia corollata. BOT. Gaz. 25:41? 
8. | ; 
‘Jahrbiicher fiir wiss. Bot. 30 : 205-226. 1897. 
> The cell in development and inheritance, 67-68. 1896. 
° Ann. Sci. Nat. Bot. VIII. 6:177-220, 7. g-r7. 1898. 
