PLANTS THAT ABE CARRIED BY ANIMALS. 71 
many of them are broken in pieces by cattle, which eat 
a portion, while other portions often adhere to the legs or 
noses and are carried from place to place. These frag- 
ments are usually capable of growing. 
The unicorn plant, Martynia proboscidia, common in the 
southwestern portion of the United States, is sometimes 
Fig. 54. — ■ Dry fruit of the unicorn plant adapted to catching on to the feet of 
large animals or the wool of sheep. 
seen in cultivation. When ripe, the fruit is hard, carrying 
two stout beaks with recurved tips. Experiments show it 
to be admirably adapted to catch on to the feet of sheep, 
goats, and cattle, or hold to the fleeces of the two former. 
44. Water-fowl and muskrats carry seeds in mud. — 
Seeds and fruits of aquatic and bog plants that are float- 
ing, or in the mud of shallow water, are often carried by 
ducks, herons, swallows, muskrats, and other frequenters 
of such places, on their feet, beaks, or feathers, as they 
