84 THE HAKMONIES OF NATUKE. 



CHAPTEE XII. 



SEEDS AND THEIR MIGRATIONS. 



Defences of Seeds. Their Dissemination over the Earth. Feathers and Wings. 

 Cotton. Influence of Water-courses. Mangrove Seeds. The Animals and Man 

 as Disseminators of Plants. Progress of Vegetation on the originally naked Eock. 



CAN anything be more admirable than the provident care be- 

 stowed upon the seeds of plants ? See how the sweet kernel of 

 the walnut is inclosed, not only in a thick coriaceous astringent 

 skin, but in a solid case of almost stony hardness ; and how 

 snugly the chesnut lies concealed, like a hedgehog under its 

 bristly coat, until, when fully ripe, it bursts the bonds which 

 held it in salutary confinement. 



The tender seminal germs are not only protected by a dense 

 envelope against the influence of the weather, so as to be able 

 to remain for years in a state of dormant vitality ; but they also 

 find within the seed itself the albumen, the oil, the starch, the 

 gluten, in one word, all the nourishment they require when 

 under favourable conditions they first awaken into active life ; 

 and thus nothing is wanting for their equipment when, dropping 

 from the parent stem, they launch forth to seek their own for- 

 tunes in the wide wide world. 



From the sedentary nature of plants, they would have been 

 menaced with extinction if nature had not provided means for 

 the diffusion of their seeds over a vast area. As the spores of 

 mosses, fungi, and lichens consist of an impalpable powder, the 

 particles of which are scarcely visible to the naked eye, it 

 is not difficult to account for their being dispersed throughout 

 the atmosphere, and carried to every point of the globe, where 

 there is a station fitted for their reception. Lichens in particular 

 ascend to great elevations, sometimes growing two thousand feet 

 above the line of perpetual snow, at the utmost limits of vegeta- 



