26 
F. E. Weiss. 
The Swedish naturalist does not base his recognition of these 
various seeds as myrmecochorous on the presence of recognisable 
elaiosomes; the great value of his monograph lies in the very careful 
and detailed experiments by which he supports his contention that 
the elaiosome is the organ that definitely attracts the ants. In the 
case of each species of plant he has made and recorded numerous 
experiments both with normal seeds and with seeds deprived of 
their food-bodies, and the evidence strongly supports his main thesis 
as to the attractiveness of the elaiosome. 
The question as to the effectiveness of ants in the dissemination 
of plants Sernander answers by observations made both in the 
South of France and in Sweden. As regards distance he has seen 
from direct observations seeds carried 15 to 70 metres; while as to 
numbers he observed near Montpellier some ants of the genus 
Aphenogaster within three hours carrying 216 seeds. In Sweden 
during nineteen hours he observed Formica rufa carrying 366 seeds 
and fruits, of which 156 were those of Melica, 69 of Melampyrum, 31 
of Luzula pilosa, 28 of Hepatica triloba, 25 of Carex digitata. 
Assuming that these ants were at work on 80 favourable days in 
the year and were to work for twelve hours a day, the total number 
of seeds transported would be 36,480. Of course many if not most 
of these seeds would be carried to the nests, around which he often 
found the seeds thrown out with the elaiosomes bitten off, but many 
are left on the way, as is well shown by a diagrammatic figure of 
the occurrence of plants bearing myrmecochorous seeds in the 
vicinity of an ant hill. To find out the number of seeds dropped 
by the way Sernander staked out a quadrat (square meter) on 
a path leading through a wood in which Melampyrum pratense was 
growing. The said path was largely used by the ants at the time 
when the seeds of the cow-wheat were mature and he counted on his 
quadrat no less than twenty-eight seeds which had been left behind. 
Sernander deals also with the ecology of the myrmecochorous 
plants, which, as stated above, are largely meadow and woodland 
plants. He finds them most common in meadow-land and 
particularly in limestone meadows, representing in some regions of 
Dalecaria as much as 40% of the vegetation. The presence or 
absence of ants therefore would seem to be an ecological factor of 
no small importance. It is interesting too to note that a large 
number of the so-called ruderal plants which settle and are found 
growing upon waste places are myrmecochorous, and this is 
particularly the case in the Mediterranean region, where no doubt 
