RELATION'S OI' AXTS TO I'ASCULAR PLANTS. 315 



time in the tropics, where all of these wonderful cases occur, are very 

 apt to jump to conclusions, and carefully devised experiments, which 

 alone can throw the necessary light on the subject, are still wanting. 



The opinion here maintained is indirectly supported by what is 

 known concerning some of the other relations that may obtain between 

 plants and ants. These relations may be considered under the follow- 

 ing heads : 



1. Ants as Seed Distributors. In the preceding chapter Mog- 

 gridge's observations on the distribution of seeds by Messor barbanis 

 were mentioned, together with other facts which indicate that ants are 

 important agents in scattering seeds. This habit is not confined to 

 granivorous species. Lubbock (1894) saw Lasins niger carrying violet 

 seeds into its nest. More recently Sernander (1903) and some other 

 botanists have come to believe that the ants eat the caruncles and that 

 these structures are developed as lures, like the extrafloral nectaries 

 and food-bodies, to induce the ants to carry the seeds to a distance and 

 thus increase the chances of their survival. Dr. E. B. Southwick tells 

 me that he has seen the ants in Central Park, N. Y., carry away the 

 seeds of the blood-root (Sanguinaria canadensis) and feed on their 

 caruncles. 



2. Ant-gardens. This name is given by Ule (1902) to certain 

 sponge-like ant-nests (Fig. 179) which he found built on the branches 

 of trees in the forests of the Amazon. These nests consist of soil 

 carried up by the ants (Azteca olithri.v, iilci and traili and Camponotus 

 feinorutns ) and held together by 'the roots of numerous epiphytes, 

 which grow out of it on all sides, making it resemble the head of a 

 Medusa. The ants not only perforate the soil with their galleries but, 

 according to Ule, actually plant the epiphytes. This he infers from 

 seeing the insects in the act of carrying the seeds. Perhaps these are 

 brought into the nest for the sake of their caruncles and then 

 germinate in the rich soil, but it is quite as probable that they are 

 sown by the wind. 



3. Plants Injurious to Ants. If it be true that some plants deserve 

 to be called " myrmecophilous," because they are helpful to ants in the 

 struggle for existence, it is equally true that there are other plants that 

 might with even greater justice be called " myrmecophobic," or li myr- 

 mecechthric," because they are injurious or even deadly to these insects. 

 Such are, for example, certain moulds and bacteria. Queen ants while 

 founding their colonies in damp cavities in soil or decaying wood often 

 succumb to the incursions of these organisms, which under certain 

 conditions may even exterminate the brood of larger colonies. Miss 

 Fielde (iQorM says: " Penicillium crustacenm grows to ripeness, in 



