84 
Improvement of the Plants of the Farm. 
ten or a dozen blooms only were impregnated in one ear. They wore all sown 
during the next autumn, and the fixing of any form which seemed promising 
went on, simply under the process of selection. Only, in order not to overtask 
the memory, an ear was preserved of each, form judged worthy of propaga- 
tion, and was kept in a glass case, which was produced the next year at the 
time of selecting the plants, so that the individuals kept in each successive 
year were as like as possible to the one chosen at first. Four or five years' 
selections were necessary, on an average, to make each sort tolerably even and 
fixed." 
I am indebted to Mr. Rimpau, of Schlanstedt, for a copy of 
a reprint of an article of his " On the Flowerino^ of Cereals,' 
which was published last vear in a well-known Prussian Agri- 
cultural Journal.* This is an exceedingly interesting and 
exhaustive article on what is known of the phenomena and 
processes of flowering of cereals, critical references being made 
to the writings of other investigators in the same direction. 
The author conducted an extensive series of observations and 
experiments on the relation of temperature and the swelling of 
the lodicules to the expansion of the flowers for fertilisation. 
\ arious kinds of wheat, rye, barley, and oats were experimented 
on. He found that the opening of the glumes of cereals, like 
all other physiological phenomena, is dependent on a certain 
temperature. That is to sav, there is a minimum below which 
the flowers will not open ; there is an optimum which most 
favours the phenomenon ; and there is a maximum above which 
the flowers will not open at all. The swelling out of the 
lodicules, which is the ultimate cause of the opening of the 
glumes, is itself dependent on the temperature. Briefly, the 
opening of the flowers, and the consequently possible cross- 
fertilisation, is due to the swelling of the lodicules, acted upon 
by the temperature — the degree of swelling invariably corre- 
sponding to the angle of opening of the glumes — and after the 
act of impregnation the lodicules shrivel up and permit the 
glumes to close over the pistil. The author also treats of the 
inconstancy and liability to reversion of the earlier generations 
of undoubted crossed varieties. Two other useful articles by 
Mr. Rimpau, each published in the same Journal in 1877, are 
that " On Raising Xew ^ arieties of Cereals," which will be 
found at p. 193 ; and another " On Self-sterility of Rye," 
p. 1073. In reply to one of my printed questions, Mr. Rimpau 
states that in Germany the improvement of cereals by crossing 
and selection has been undertaken by Mr. F. Heine of Emers- 
leben, near Halberstadt, who has raised by ear-selection a good 
variety of summer wheat. 
English farmers may be gratified to learn that many of the 
♦ ' Landwirthschaftliche Jalu^bucher ' (1883), xi. pp. 875-919. 
