MESSMATES, MUTUALISTS, AND PARASITES 97 
Some animals store-up seeds and fruit for future use, and as 
for various reasons many of these escape being eaten, the storing 
habit undoubtedly promotes dispersal. Squirrels, jays, and many 
ants may be cited in illustration. The case of ants is peculiarly 
interesting. According to Kerner’s observations the seeds which 
prove attractive to these little creatures are those which, although 
smooth, possess a little rough outgrowth technically known as a 
“caruncle”, as in Violet, Greater Celandine, Snowdrop, Peri- 
winkle, and some Spurges. It is only this caruncle which is 
eaten, the rest of the seed being left untouched, and capable of 
germination. 
Besides the seeds and fruits which specially appeal to the 
appetites of animals, there are many others which become attached 
to their bodies, and are thus effectively dispersed. This may 
take place without any special adaptations to clinging, as in the 
case of the floating seeds of many aquatic plants, which adhere 
to the plumage of birds, or where moist earth 
containing seeds sticks to the feet of birds or 
other animals. 
There are, however, a large number of fruits 
and seeds which are either sticky or else studded 5. oe _-Fruitof Liv. 
with hooks, their chances of transport by animals 22 éoreatis (xs) stodded 
with glandular hairs 
being thus greatly increased. Stickiness results 
in many cases from exposure to moisture, as in the seeds of Meadow 
Saffron (Colchicum) which have often been observed adhering to 
the feet of sheep, cattle, and horses. A somewhat more special- 
ized case is afforded by fruits which owe their viscidity to the 
presence of glandular outgrowths, e.g. Linnea borealis (fig. 1086). 
A firmer means of attachment is found in seeds and fruits 
provided with hooks, and its efficiency would seem to be proved 
by the fact that about ten per cent of Flowering Plants are pro- 
vided with such arrangements. They have apparently been 
evolved, at least in many cases, in relation to the hairy coats of 
Mammals, for they are particularly characteristic of plants of 
low stature, with which such animals are likely to come into 
contact. Many examples are found among the members of our 
native flora, as everyone who knows the country must have 
observed. The little globular fruits of the Goosegrass or Cleavers 
(Galium aparine, fig. 1087) are studded with little recurved 
bristles which prove very effective holdfasts, and the “burrs” 
Vou. IV. 101 
