134 FIRST STUDIES IN PLANT LIFE 



11. How a grass-seed may sow itself. On the 

 ripe seed of sweet vernal 

 grass and some other grasses, 

 there is a bristle or awn. 

 Sometimes this bristle is rough 

 enough to catch on to animals, 

 but its main use is to bury the 

 „,,,., ^ ,, ■ seed in the ground ! The plan 



Floret of the oat showing c5 ± 



*"'°''- is quite simple. When dry, 



the awn coils up ; but when damp from dew or rain, 

 straightens itself out again. Every time this change 

 takes place, the seed crawls and wriggles, and is some- 

 times in this way pushed into sand or into a crack 

 where the rains may cover it Avith soil. 



Questions and Exercises . — 



(1) Name any plants that spread in rosettes smothering 

 smaller plants. 



(2) Take ripe seed of gorse or dolichos or balsam indoors, and 

 try to measure how far the seed is thrown. Wliy is the garden- 

 balsam called Toicch-me-tiot ? 



(3) Compare the following pods that jerk seed ; Gor^e, field- 

 sorrel, dolichos, common broom. 



(4) Dock-weed seed are borne do\\Ti a river. A single seed of 

 the dock sinks when put into water ; (try it). Explain Nature's 

 plan for making it float. 



(5) Can you find any other plants that live on river-flats that 

 have " floats " of any kind for their seed ? 



Composition exercise: — Write the story of a silver wattle 

 pod that travelled down a river and made a new tree. 



Drawing exercise : — Draw a dolichos pod (a) before it has 



thrown its seed ; (6) after it has thrown its seed. 



