Seed-Scattering 219 



when the air is almost absolutely motionless, so extremely 

 light are they, being, in fact, rather like pollen than seeds. 

 Spores, owing to this extreme lightness, travel immense 

 distances over sea and land, and are to be found in almost 

 all dust, whether of town or country; but in damp weather 

 they are not carried so far, and some of the mosses keep 

 the capsules in which their spores are contained tightly 

 closed except when the air is dry enough to msure them 

 a long journey. 



It might seem that large, heavy seeds would be at a 

 disadvantage in respect of wind transport; but as they 

 need a stronger shake to detach them, they do not begin 

 their journey till the wind is blowing with some little force; 

 and then again, being generally borne by trees, and tall 

 trees, too, they start at a favorable height, and are often 

 carried a long way. 



But we have been looking upon seeds hitherto as if 

 they were themselves perfectly helpless and inactive, which 

 is very far indeed from being the fact. Many of them 

 have special means of their own for insuring or helping 

 their conveyance from place to place — means which vary 

 according to the carriers upon which they depend for 

 locomotion. 



Those which are carried by the wind, for example, 

 have elastic spines, wings, feathery tails, down, hairs, all 

 of which help to speed them on their way, and make it 

 more easy for them to be raised in the air, or blown along 

 the ground. 



Generally as the lower part of the pistil ripens, the 

 upper part withers, having done its work of conveying 

 pollen to the ovules. But sometimes the pistil-stalk 

 remains attached to the ovary, and is turned to a fresh 



