246 REPORTS ON THE STATE OF SCIENCE, 1914. 
its relations to the glabrous and fully-hoary forms. A new half-hoary 
race, which has been obtained after some difficulty, has made it possible 
to design a complete series of experiments, which is now in progress. 
(2) The further study of the gametic coupling already shown to exist 
between the factors for double-flowers and plastid-colour. This in- 
vestigation promises to give results of great interest, but a further 
generation must be raised before a statement can be made. 
(3) A result of some interest is the discovery that the double- 
flowered plants, at least in some strains, have a more rapid and vigorous 
growth than the singles. It is thus possible, by means of selection 
based on this difference, to obtain a far higher percentage of doubles in 
the flower-bed than would be expected from the normal output of 
doubles by a double-throwing single. 
(4) A beginning has also been made with the work of obtaining a 
complete series of types of known factorial constitution, so that a supply 
of material may be available for testing the view which has been put 
forward as to the inter-relations between the factors determining hoari- 
ness and sap-colour. 
Experiments with foxgloves have been designed for the investigation 
of a curious condition of partial hoariness, as well as for observations 
on the range of variability in the heplandra form. 
Experiments by Mr. Gregory with Primula sinensis have been 
designed chiefly with a view to the investigation of the cytology and 
genetics of certain giant races, which have been shown to be in the 
tetraploid condition; that is to say, they have 4x (48) chromosomes in 
the somatic cells and 2x (24) chromosomes in the gametic cells, whereas 
in the diploid races the numbers are 2x (24) and x (12) respectively. 
These experiments have given results of very great interest, which may 
be briefly summarised by saying that the reduplication of the chromo- 
somes has been found to be accompanied by a reduplication of the 
series of factors, An account of this work has been published in the 
‘Proc. Roy. Soc.,’ B., Vol. 87, p. 484, 1914, and it is hoped that a 
further statement will be made at the meeting of the British Association 
in Australia. Further experiments with these tetraploid plants are 
designed especially to investigate the phenomena of coupling and repul- 
sion between certain factors. These experiments promise to yield 
results of very great interest, both as regards the genetics of tetraploid 
plants and as regards cytological theory as to the possible relations 
between factors and chromosomes. 
In the experiments with the ordinary diploid races, an interesting 
case has been discovered in which the coupling between the factors for 
magenta and green stigma is on the system 7:1; whereas in a very 
large number of other experiments the coupling (or repulsion) between 
these factors is of a very low order, apparently less than 3:1. 
A paper is in the course of preparation, and will shortly be 
published in the ‘ Journal of Genetics,’ on the inheritance of green, 
variegated, and yellow leaves in Primula. The variegated plants consist 
of a mosaic of two kinds of cells, respectively like those of the pure 
green and pure yellow-leaved plants. The. characters of the chloro- 
plasts, on which greenness and yellowness depend, have been found to 
