FRUITS REPLACED BY OFFSHOOTS. 



455 



the time of harvest, and the haulm laid flat on the ground, the embryos beoin to 

 develop whilst the grain is still in the ear. This premature germination, however, 

 is quite independent of the parent plant, which has given up all its food-materials, 

 and is already dead; the grains, held between the glumes mechanically, are no 

 longer in vital connection with the plant which gave them origin. Their germina- 

 tion between the damp husks is similar to what would occur between pieces of 

 moist blotting-paper. But in these so-called " viviparous plants " the phenomenon 



Fig. 342.— Bulbils replacing flowers and fruits. 



nivalis with rosettes of little green leaves instead of flowers (natural size). 2 Two of these rosettes, enlarged; one 

 of these has become detached from its stalk, s Saxifraga cernua (natural size). * A cluster of bulbils of this plant. 

 ^ «. ' Bulbils of same in various stages of development, s Poa alpina with bulbils replacing its flowers (natural size). 

 9 A portion of the iuttorescence (enlarged), i" A miniature grass-plant developed between the glumes of a spikelet of Poa 

 alpina (enlarged). 



is quite different from this " sprouting " of cereals. In them no flowers or seeds are 



formed, consequently there can be no germination of seeds still united to the parent 



plant. The detached structures, formerly regarded as germinated seedlings, are in 



I reality little, leafy shoots which have been produced instead of flowers and fruits. 



j The plants which we have just been discussing are essentially forms living in 



j high alpine and arctic regions, that is to say, in regions in which they have but 



1 some two to four brief months in the year in which to complete their vital 



processes. In the majority of plants growing under such inhospitable conditions. 



