X70 PHYSIOLOGICAL BOTANY. PART II. 



CHAP. VI. 



I t MTION OF REPRODUCTION CONTINUED. Periods 4,'5. 



DISSEMINATION (275.). MODES OF DISSEMINATION (279.) 



PRESERVATION OF SEED (281.). GERMINATION (283.). 



VITAI.ITT OF THE EMBRYO (29O.). RELATION OF BTI) AM) 

 EMBRYO (291.). PROLIFEROUS FLOWERS (292.). HY- 

 BRIDS (295. . 



FOURTH PERIOD OF REPRODUCTION. 



(275.) Dissemination. THE manner in which the 

 ripe seed is disseminated, forms a more important ele- 

 ment in the history of the preservation of species than 

 might at first be imagined. It may be considered ana- 

 logous to the period of labour in the animal kingdom, 

 and still more strictly to the laying of eggs among such 

 as are oviparous. If the different modes of dissemina- 

 tion were not in harmony with the peculiar character of 

 the species, we might expect in the lapse of ages that 

 some combination of Circumstances would arise which 

 should so far interfere with the reproduction of a given 

 species that it would disappear from the earth. This 

 is guarded against by some peculiar adaptation of the 

 mode in which the seed is disseminated to the con- 

 ditions under which each species naturally thrives the 

 best. In some cases, the seed falls immediately around 

 the parent plant ; and *vhere many seeds are contained 

 in the same seed-vessel, the young plants come up in 

 a crowded manner and occupy the soil in society, to 

 the exclusion even of more robust species. Other seeds 

 and seed-vessels are furnished with the means of being 

 transported by the influence of the wind or by some other 

 cause to a considerable distance. The great diversity in 

 the means by which the dissemination of the seed is na- 

 turally secured forms one important inquiry to the bota- 



