224 THE POPULAR SCIENCE MONTHLY. 



Berries are the favorite food of many of our native mammals, the 

 woodchuck and others. Wild apples are frequently carried off 

 by squirrels, and it is well known that squirrels store up large 

 quantities of nuts which oftentimes are never eaten. Fruits too 

 large to be swallowed by most birds are easily devoured by the 

 larger mammals, the apple, for instance, whose seeds are protected 

 by tight husks well adapted to slip through the alimentary canal 

 of an animal without receiving the least injury. 



The gourd fruits, so much liked by man here, are equally at- 

 tractive to his quadrumanal brothers in the tropics. 



For utilizing the services particularly of mammals many 

 fruits have developed hooks or horns to catch in the fleece of 

 passing creatures, who thus transport the seeds from place to 

 place. An autumn tramp through our pastures will soon con- 

 vince one of the efficiency of this mode of dissemination. 



A very familiar example of this kind we find in the common 

 burdock ; but the hooks of the burdock are insignificant affairs 

 compared with some which exist. In the Southern States grows a 

 fruit, Martynia proboscidea, having two recurving horns several 

 inches long. The appearance of the fruit would justify its having 

 an even more formidable name. Another fruit, HarpagopJiyton 

 by name, is a bristling mass of powerful hooks. It is said that 

 lions trying to free themselves from its clutches get it into the 

 mouth and die in torture. Instead of hooks, seeds sometimes 

 effect the same purpose by being sticky. 



It is a suggestive fact that hooked fruits occur on low plants, 

 never on trees ; also that in geologic time hooks appeared simul- 

 taneously with land mammals. 



Lastly, we must recollect that man himself disseminates seeds 

 in a thousand ways. War often introduces new plants into a 

 region. Commerce is of vast importance in this respect. In the 

 vicinity of our woolen mills a strange flora, from seeds intro- 

 duced with the raw wool, is struggling with native plants. Agri- 

 culture is certainly of unbounded effect in the way we are consid- 

 ering. In short, human will has almost limitless control over the 

 circumstances of plant life. 



After dispersion most seeds simply rest on the ground to await 

 germination, perhaps protected by color resemblance, as in nuts, 

 or by mimicry, sometimes mimicking a dry twig to perfection. 

 Some seeds, though, do more than this. The parasitic seeds of 

 the mistletoe, dropped by birds on the boughs of trees, would soon 

 fall to the ground and die were they were not very sticky. The 

 seed of Mysodendron has three long, flexible appendages which 

 twine round any suitable branch to which it is blown. 



There are a few seeds which literally corkscrew themselves into 

 the ground. One of our natives Erodium, or cranesbill has 



