SEED DISPERSAL BY WIND 123 



CHAPTER XXXI 



SEED DISPERSAL BY WIND 



IN order that seeds may be carried any appreciable dis- 

 tance by the wind, they must be rendered buoyant. The 

 structures existing for this purpose may, for the most part, be 

 classed under three heads, wings, tufts of hairs, and blad- 

 ders. These are more often, perhaps, attached to the fruits, 

 but may, also, be attached directly to the seeds. 



I. Samara, or Key Fruit. Examine dry, ripe fruits of 

 Ash, Elm, Ailanthus, or Maple and notice : 



1. The swollen seed-bearing portion and 



2. The flattened wing. 



3. Throw up some specimens into the air and notice the 



twirling motion which helps to support them for 

 some distance. 



4. Make a sketch of the fruit studied, to show the parts 



and describe the motion in the air. 



II. "Winged Seeds. Examine some of the dry seeds of 

 Catalpa, Yam (Dioscorea), Butter-and-Eggs (Linaria), 

 Trumpet Creeper, Day Lily (Funkia), or of the Pine or 

 Cypress, and notice : 



1. The compressed seed-bearing portion, with 



2. The broader or narrower wing. 



3. Make a sketch tp show these characters. 

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