122 



BIOLOGY FOR BEGINNERS 



Seed dispersal. 



No. 1. Maple "key," one of a pair of fruits which separate as they fall. 

 They whirl in a horizontal plane, and so fall slowly and are blown to some dis- 

 tance. The heavy end works down to the ground, giving the enclosed seed a 

 chance to germinate. 



No. 2. Pine seed. Not a fruit, like the maple, though dispersed in the 

 same way. Shaken out of the cone when ripe. 



No. 3. The Bass-wood. A group of fruits, with a parachute which lets 

 them fall slowly and so reach some distance, also it will drag them some farther 

 after alighting, especially on a "crust" in the winter. 



No. 4, Clematis and No. 5, the Dandelion, are both fruits with parachutes 

 made of downy hairs. The Milkweed has a similar device on its seed. 



No. 6, the Bladder-nut and No. 7, a Sedge, are both provided with water- 

 tight life preservers, which float the seeds to distant landing places. Bladder- 

 nut is also light enough to blow. 



No. 8. The Poppy fruit, has many tiny openings at the top of its "pepper 

 box" capsule. The stem is stiff and springy and the small heavy seeds whip 

 out in the wind, a few at a time, assuring at least some of them, favorable 

 conditions. 



