188 



ELEMENTS OE 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. Kg. 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, Pig. 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 

 hair.s ? 



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, i 



Fig. 173.— Fruit-Cluster of Linden; peduncle 

 joined to the bract, forming a wing. 



' See Kerner and Oliver, vol. II, pp. 833-875. 



