470 BOTANICAL GAZETTE [JUNE 
Bordeaux mixture on the leaves. The depression of the yield increased with the 
strength of the mixture applied. Asa rule, the beneficial effect of the mixture 
has been ascribed to the shade-effect of the covering, which was supposed to 
protect the plants from too great an intensity of light. LEwerrt found that 
bean plants shaded by a light gauze during periods of greatest illumination 
gave a greater yield and retained their leaves longer than unshaded plants. 
A similar effect produced by a covering of Bordeaux mixture, he thinks, would 
be counterbalanced by the ill effects of the shade on cloudy days and the toxic 
effects of the copper. In the experiments with currants, it was found that 
spraying berries with Bordeaux mixture or dipping them into it increased their 
sugar content considerably. How this effect is brought about is not yet clear. 
This effect on the berries is so striking that a decrease in their sugar content, 
due to depression of the assimilatory activity resulting from spraying the leaves, 
can be easily overlooked. Two sprayings of the leaves with 4 per cent mixture 
resulted only in a decrease of 0.5 per cent in the sugar content of the berries 
which were protected from the spray. This decrease is attributed to the 
deleterious effects of ihe mixture on the assimilatory activity of the leaves.— 
H. HASSELBRING. 
Dispersal of seeds by ants.—SERNANDER* organized the disjointed and 
inaccurate data on the importance of ants in the distribution of certain seeds 
and fruits, and added a wealth of observations and experimental evidence upon 
this phase of ecological science. This particular kind of distribution he termed 
“‘myrmecochorous,”’ and showed that it was almost wholly due, not to the 
supposed mimicry of the pupa of ants by the seeds, but to the presence of 
certain oil bodies or “‘elaiosomes” which serve as food for the ants and hence 
cause their collection and storage. These bodies occur as various morpho- 
logical modifications or appendages of seeds and fruits, various types being 
distinguished. Some 120 plants were at that time listed as myrmecochorous, 
and evidence was produced that the activity by a single colony of ants for one 
season includes the transportation of many thousand seeds, some to distances 
of 15 to 70 meters. 
A recent article by Morton” calls attention to the important foundation 
laid by SERNANDER, cites the contributions that have appeared since that 
date, and summarizes the present situation of m cochory. The number 
of myrmecochorous plants has been considerably increased, although these 
studies have been almost exclusively confined to Europe. The associations 
affected are mostly those of woodland and ruderal plants. Morron concludes 
that ants have been acting as a selection factor for such plants at least since 
ANDER, R., Entwurf einer oe der europiischen Myrmekochoren. 
oo Vetenik. Abad. Upsala 41: 
22 MorTON, FRIEDRICH, Die acs der Ameisen fiir die Verbreitung der 
Pflanzensamen. Mitt. Naturwiss. Vereins 1912:77-112. Reprint by author, 1913. 
