278 FREAKS OF PLANT LIFE. 



feathered upper part is carried round, so that the 

 movement is conspicuous. As the moisture evapo- 

 rates, the twisting of the lower portion of the awn 

 again takes place, and the twisting and untwisting 

 may be repeated at will, as moisture is applied or 

 withheld. If the feathered end of the awn is fixed, 

 and the seed is free, the latter will be carried round, 

 rotating with the movement of the twisting or un- 

 twisting awn. The object of the investigations allu- 

 ded to was to determine what was the reason for this 

 twisting, and what purpose it served in the economy 

 of the plant. Without entering into ' the details, 

 which may be consulted at will, it may be assumed 

 as proved that the hygrometric property possessed 

 by the awn, whereby it twisted and untwisted, would 

 enable the sharp point at the lower extremity of the 

 seed to penetrate and bury itself in the ground. It 

 was shown by experiment " that the seed was buried, 

 both as it untwists, and also as it returns to a state 

 of torsion. By a combination of these two processes 

 the awn is thrust into the soil to such a depth as to 

 cover up the seed completely." A seed entangled in 

 the branches of a low bush, and left out of doors for 

 eight days, had buried itself to a depth of thirty-one 

 millimetres, or nearly double the length of the seed, 

 impaling a piece of rotten leaf in its way. It was 

 found that seeds dropped from a height of a few feet 

 usually preserved a nearly vertical position, striking 



