THE FRUIT 105 
Winged seeds are found in Bignonia, Tecoma and 
Pinus, and plumed seeds in Asclepias, Gossypium, Epi- 
lobium and Oleander. 
71. Dispersal by Animals.—Animals and birds either 
carry the fruit away involuntarily, or eat it and drop the 
seed. To the latter class belong all the succulent fruits. 
It will be noticed that these fruits usually develop a 
bright attractive colour when ripe, but when unripe 
they are usually green, and therefore not conspicuous. 
The seeds are all protected by a hard indigestible cover- 
ing, so that if swallowed they will pass uninjured 
through the animal’s alimentary canal. Most succulent 
fruits are dispersed by birds, and are found on shrubs 
and trees, a few only are eaten by otheranimals. Fruits 
which are carried away by animals are usually provided 
with hooks or spikes. To this class belong the various 
burs, found on the veldt, and there are many other 
hooked fruits found in South Africa, eg. Martynia 
(fig. 59), Bidens (Black Jack), and Medicago. Some of 
these hooked fruits are very troublesome to wool-growers, 
for example, Xanthium, which is a proclaimed weed in 
South Africa, and farmers allowing it to grow on their 
land are liable to a heavy fine. Harpagophytum (the 
Grapple plant) is almost equally troublesome, but not 
so common. : . 
72. Dispersal by Water.—Fruits dispersed by water 
are found chiefly in aquatic plants. They are not 
common. The fruit of Luffa cylindrica has a light, 
spongy mesocarp and a waterproof epicarp, which en- 
able it to float for long distances on the water without 
the seeds being injured. This fruit furnishes the well- 
