118 THE AMERICAN BOTANIST. 



Ant Plants. — A few years ago, nothing seemed surer, in 

 the stories of returned travellers and botanists, than the fact 

 that certain species of tropical plants maintained body guards 

 of stinging ants as a defense against leaf-eating animals and 

 in return for their services fed and housed the entire regiment. 

 Recent unsentimental students of this matter assert that the 

 plants can get along without the ants quite as well as a dog 

 can without fleas and thus all the "adaptations" which the 

 plants were supposed to have evolved with reference to the 

 ants must be translated in some other way. The ants, how- 

 ever, are said to be completely adapted to the plant and do 

 not seem to prosper at all without them. If the plants derive 

 any advantage from the presence of the ants this seems a mere 

 incidental. In this connection it may be observed that we have 

 an ant-plant in the Northern States in the form of the blazing 

 star (Liatris scariosa). In old plants the center of the tuberous 

 underground parts usually decays and almost invariably the 

 cavity thus found is inhabited by a colony of ants. The pres- 

 ence of these ant colonies doubtless keep various creeping in- 

 sects away from the plants, but the benefit is not apparent for 

 other plants that lack a colony prosper in spite of it. 



Weed Seeds. — In a general way we are familiar witli the 

 fact that every wild species maintains its existence only by a 

 constant struggle, but we seldom fathom the depth of the 

 struggle. A grass field, for instance, looks peaceful enough, 

 but a moments reflection will convince that the plants in this 

 particular field are here only because they are the surs'ivors or 

 rather victors of a thousand battles in which uncounted multi- 

 tudes have gone to their deaths. These battles have possibly 

 been waged most fiercely between plants of the same species, 

 but there are other battles of species with species, of plant 

 with insect of plant with cold and drouth and heat and food. 

 The pistils of necessity must receive the precious pollen, and 



