196 



STUDIES IN SEEDS AND FRUITS 



Withered 

 leaves and 

 dried seeds 

 are in the 

 same 

 category. 



Excluding the Pine seeds, which are not strictly comparable 

 with ordinary winged seeds, we observe that in the three types 

 of seeds here exemplified the weights of these appendages vary 

 in amount between 4 and 14 per cent, of that of the entire 

 resting seed. The wings are here greatly developed, so we 

 may infer that in ordinary "margined" seeds, where the alar 

 appendage is reduced to a narrow border, there is very little 

 addition to the seed's weight. Now wings are functionally 

 useless as we observe them in the resting seed, or we may put 

 it in another way, and say that though actively functioning 

 in the soft living seed within the living fruit, they have no 

 biological significance in the dry seed of the withered fruit. 

 Being dried up and dead they could only serve an accidental 

 function in a resting seed which is practically in the same 

 condition. A more natural comparison of these types of 

 winged seeds would therefore be obtained by contrasting 

 them in the living moist condition within the fruit when the 

 wings are actively functioning organs. In the resting seed 

 the wings are dead and dried up and could only serve acci- 

 dental ends. 



As far as the capacity for transportal by wind is concerned 

 the withered leaf and the dry winged seed are in the same 

 category. That the seed possesses the power of reproducing 

 the plant is an accident as regards its fitness for wind- 

 transportal. The puff of wind will carry along both the 

 seeds that are germinable and the seeds that have lost this 

 power ; and we cannot distinguish between them as respects 

 either appearance, weight, or size. Yet the dispersal of 

 seeds by winds is real enough. The seeds of Tecoma stans^ 

 which are about an inch long, weigh just about the same 

 as a piece of newspaper cut to the same size. The wind 

 when strong could carry them great distances, and the like 

 may be said for the seeds of the Pine. The much heavier 

 winged seeds of Moringa^ as experiment shows, are but little 

 aided in this way by their appendages. In an ordinary 

 breeze a Mahogany seed as it falls out of the dried dehiscing 



