F. E. Weiss. 
24 
on those of Melampyrum pratense, of Kerner 1 on Chelidonium and 
others, Sernander proceeds to classify the very large number of 
other fruits and seeds which he has been able to add to the 
previously short list of seeds known to be myrmecochorous. The 
attraction which these seeds have for ants he attributes to the 
food, largely of an oily nature, which practically all myrmeco¬ 
chorous fruits or seeds provide in more or less accessible form, 
the supposed mimicry of the pupa of ants by certain seeds, such as 
those of Melampyrum he considers as possibly accidental. The 
seeds of Melampyrum are provided with an elaiosome, the removal 
of which, as well as of the oil-containing seed-coat retards the 
collection of the seeds by the ants in much the same way as is the 
case with other myrmecochorous seeds. 
In the most striking, and possibly also the most numerous 
cases, the seeds are provided externally with definite food bodies or 
elaiosomes (sXouov = oil; <rcvpa = body), which in the form of crests, 
caruncles or strophioles are characteristic of certain groups 
of seeds. 2 In some plants, however, where no distinct elaiosomes 
are present, fatty oils are to be found in other parts of the seed, 
or fruit, or in some other organ connected with the latter. A brief 
review of the various types distinguished by Sernander will perhaps 
give the best idea of how the “dispersal-units” are rendered 
attractive to ants. 
We have (1) the Pusclikinia type in which the delicate seed- 
coat is impregnated with oil. This group includes besides the 
above mentioned genus, some Liliaceas, such as Allium ursinum, 
and several species of Ornithogalum. 
(2). The Viola odorata type in which a portion of the seed 
forming a strophiole or caruncle is developed as an elaiosome, is 
probably the largest, as well as the most striking, group of myrme¬ 
cochorous seeds. To it belong a number of Monocotyledons, such 
as various species of Chionodoxa, Lachenalia, Scilla, Galanthus 
nivalis and Ltizula pilosa. Of the Dicotyledons, Arenaria, Reseda 
odorata, Chelidonium majus and several species of Corydalis and 
Viola may be mentioned. In some cases the elaiosome is formed 
by the crested funicle. This is the case in the seeds of the primrose, 
in which a portion of the seed-coat also contains oil. 
1 Kerner and Oliver. Natural History of Plants, 1895. Vol. II., 
p. 866. 
2 Robertson, Ch. Seed Crests and Mymecophilous Dissemi¬ 
nation of Certain Plants. Botanical Gazette, Chicago, 1889. 
