100 BOTANICAL GAZETTE : [FEBRUARY 
thus be possible after a time to decide whether they result from 
hybridization only, or whether they may be the result of some other 
constitutional derangement caused by cultivation. It should be 
mentioned in this connection that Miss Lyon (16) described five and 
six spores in a mother cell of Euphorbia corollata, which is a common 
species in this region. In this case the daughter cells are stated to 
be all of the same size, however, which suggests that the number 
may have been produced by extra divisions of one or more of the 
daughter cells, rather than by some of the chromosomes becoming 
scattered in the cytoplasm. The same explanation may apply to 
some of the other forms mentioned; and it is also necessary to assume 
extra divisions in cases such as Lonicera coerulea, where as many as 
fourteen daughter cells are figured in one mother cell. FULLMER (7) 
thought that such extra mitoses would account for most of the condi- 
tions in Hemerocallis, but in this he was probably incorrect. 
A more careful study of some of these forms, and of some of those 
said to produce only one, two, or three pollen grains from a mother 
cell, as described in the paper of JueL (14) on Carex, would doubtless 
furnish many interesting results and aid in a determination of the 
causes of these irregularities. 
THE PHENOMENA OF POLLEN DEGENERATION 
During the last few years a number of cases of sterility in the 
pollen of hybrid plants have been described, with interesting morpho- 
logical and cytological results. JuEL (13) in 1900 described pollen 
development in the sterile Syringa Rothomagensis, which is a cross 
between S. vulgaris and S. persica. He also studied the corresponding 
stages in the parents for comparison. In S. vulgaris only about 
50 per cent. of the pollen grains were found to be normal, and in 
S. persica good grains were few. Practically the same conditions 
of development were found in S. persica as in the hybrid. A great 
variety of irregularities in the reduction divisions was found in the 
hybrid. As in O. lata, the degeneration sometimes began as early 
as the synapsis stage, but generally the tetrad divisions were com- 
pleted. A drawing apart of the nucleus into two may occur in the 
spirem stage or after the spirem has segmented into chromosomes. 
The latter at least could not be called amitosis. In the first reduction 
