424 BIOLOGIC RELATIONS BETWEEN PLANTS AND ANTS. 



nectar have none. In other plants the leaves form about the stem a 

 sloping surface in the form of a collar, or the vegetative organs may be 

 covered with a waxy secretion that renders the leaves and stems, 

 or perhaps both of these organs, shining, smooth, and slippery. The 

 myrmecophobic function of these slippery surfaces has been shown by 

 Delpino, although, as it seems to us, he has in a number of cases 

 exaggerated the defensive role attributed by him to the glaucescence 

 of the vegetative organs. In certain cases the glaucescence may be 

 combined with another method of protection. Such is the case with 

 the Bicinus or castor-oil plant, whose leaves are nectariferous and whose 

 stem is glaucous (Delpino and Schimper). 



If flowers with large corollas were visited by ants they could not 

 usually be visited by winged insects, who are alone suited to effect 

 pollination. A bee, for example, who might light upon a flower thus 

 visited by ants might run the risk of having its proboscis, one of the 

 most sensitive of organs, seized by the ants; hence the utility, for many 

 insect-loving flowers, of protecting themselves against the visit of ants. 

 In a considerable number of cases the protection is effected by foliary 

 organs, as we have just indicated, but more frequently the plant pro- 

 tects itself. Pendent flowers having the peduncle inclined toward the 

 ground offer by the very curvature of that organ an arrangement very 

 likely to cause the fall of ants who may venture upon it. Besides, these 

 plants are usually slippery. Good examples of this arrangement are 

 observed in the snowdrop (Galanthus nivalis), the Cyclamen, the crown 

 imperial (Fritillaria imperialis). These plants protect themselves as 

 does the weaver bird, which places its nest upon the end of a flexible 

 limb, where it will be out of the reach of serpents. If a flower is 

 arranged horizontally or vertically it may protect itself by means of 

 viscous hairs upon which the ants will be likely to stick. We may 

 cite as an example of surfaces thus covered with granular, viscous 

 bairs the peduncle of Silene nutans, of Epimedium alpinum, the flowers 

 of the gooseberry, of the Linnaea borealis, of the Plumbago Europea, a 

 plant considered by some authors as insectivorous (?). 



Aquatic plants are protected by their very situation. Aquatic species 

 of genera generally pubescent are smooth. Examples: Viola palustr is, 

 Veronica anagallis, Veronica beccabunga, Ranunculus aquatilis. In the 

 Polygonum amphibium, studied by Kerner, the stigma is much larger 

 than the corolla. If the ants should penetrate the interior of this 

 corolla they would steal the nectar without pollenizing the plant; but 

 if a winged insect should visit the flower there would be many chances 

 of its brushing the stigma in its passage. The stamens are short and 

 ripen before the pistil, so that any winged insect, however small, can 

 effect pollination. But this Polygonum, as 'its specific name indicates, 

 may also grow upon the land. As long as it remains in water it remains 

 glabrous; as soon as it grows upon the land it becomes covered with 

 glandular hairs. 



