THE COSMIC ADAPTATION OF THE SEED 451 



tell, it is certainly this. Similarly, it is the contraction of the 

 life-conditions, the waterless, sandy soil, the intense insolation, 

 etc., that has reduced Welwitschia to little more than a gigantic 

 embryo. There are seeds, like those of Poinciana regia, as 

 described in Chapter XIX, where, before the rest-period is 

 imposed, the embryo, as far as the production of plumular 

 leaves is concerned, attains a more advanced stage of develop- 

 ment than we find in the adult Welwitschias. 



Althoup-h plant-types, for all we know, may be eternal, the The plant is 



, 1 • 11 .. ^ -^ 1 f -ui least mutable 



seed represents the only immutable, or, to put it less torcibly, on its cosmic 



the most persistent part of a plant. Excluding its coverings ^^"^/j'.^^'"'*^ 



and appendages, it remains unaltered either under diversified 



conditions or in the lapse of the ages. Plants are often thus 



connected which have seemingly little else in common. Take, 



for instance, the Tillandsias, which vary so greatly in form that 



if it were not for the flower and the seed we should probably 



never connect them. It is the cosmic characters, the seed with 



the preparatory flower, that tend to link plants together. It is 



in its cosmic characters that the plant is most persistent and 



least mutable. 



We possess in our plant-world a scale of possibilities Theter- 



i , . . r Tf • ^1 ..• restrial scale 



ranging from the seeming suspension ot lite in the resting ofpossi- 

 seed to the full development of vegetative life in the tall ^1^^^%?^^ 

 forest trees, where, in extreme cases, as in those of Sequoia^ the 

 evenly preserved balance of growth and decay gives promise 

 almost of eternity. There may be but little diff^erence 

 between the apparent suspension of Hfe in the seed embryo 

 and the calm repose of the life forces in Sequoia, where the 

 organisms seem to be so nicely adjusted to its conditions. 

 The vital processes, subdued though they be in the tall Sequoia, 

 may be only proportionately less active than what actually takes 

 place in the embryo shut up in its hard coverings. Recent 

 discoveries in physical science would justify us in regarding 

 the possibiUty of other means of communication between the 

 embryo and the outer world than those concerned merely with 

 respiration, transpiration, and the ordinary nutritive processes 



