188 ELEMENTS OF BOTANY. 
the seed is surrounded. Hence a general division of fruits 
into dry fruits and fleshy fruits. 
227. Winged or Tufted Fruits and Seeds. — The fruits of 
the ash, box-elder, elm, maple, Fig. 172, and many other 
trees are provided with an expanded membranous wing. 
Some seeds, as those of the catalpa and the trumpet-creeper 
are similarly appendaged. The fruits of the dandelion, the 
thistle, the fleabane, Fig. 174, and many other plants of the 
group to which these belong, and the seeds of the willow, 
the milkweed, the willow-herb, Fig. 175, and other. plants, bear 
a tuft of hairs, sometimes silky and in other cases plumed or 
feathery. 
The student should be able from his own observations on the falling 
fruits of some of the trees and other plants above mentioned to answer 
some such questions as the fol- 
lowing : 
What is the use of the wing- 
like appendages ? of the tufts of 
hairs ? 
Which set of contrivances 
seems to be the more success- 
ful of the two in securing this 
object ? 
What particular plant of the 
ones available for study seems to 
have attained this object most 
perfectly ? 
What is one reason why many 
plants with tufted seeds, such 
as the thistle and the dande- 
lion, are extremely troublesome 
weeds ? 
A few simple experiments, 
easily devised by the student, 
may help him to find answers 
to the questions above given. 
Fia. 173.— Fruit-Cluster of Linden; peduncle 
joined to the bract, forming a wing. 
1 See Kerner and Oliver, vol, II, pp. 833-875. 
