48 THE BOTANICAL MAGAZINE LVoi. xxxvi. No. 425. 



the root cap. From Fig. 1, it can be seen that the hairs are developed 

 in various parts of the coleorhiza, and apparently every cell of the 

 epidermal layer of the coleorhiza is able to produce hair. 



The development of both the coleorhiza and its hairs varies with 

 the medium in which it grows, and these variations accord with the 

 usual root behavior. 



It was observed that the coleorhiza becomes more extended in 

 water than in air, and this is true to a slight degree of its hairs. 

 A reversed ratio, however, exists between the root hairs developed in 

 water and air, as observed by Snow 29-30 (1904). This difference in growth 

 of the coleorhiza hairs and root hairs in the two media, water and 

 air, gives quite a different aspect to the seedling : in air, there is a 

 strong growth of root hairs, and coleorhiza hairs just appear on the 

 epiblast. The diameter of the coleorhiza hairs and root hairs grown 

 under these conditions shows slight variation, but as a rule the 

 coleorhiza hairs exceed the root hairs both in diameter and length. 



The development of coleorhiza hairs is not influenced by light 

 intensities. They show no difference when grown in the light and in 

 the dark, and these reactions correspond with the results obtained 

 by Snow 30 " 31 (1904) and Bardell 1 (1915) on root hairs. 



It is evident that these coleorhiza hairs are the analogues, physio- 

 logically, of the root hairs, and that they serve as a unique device 

 for putting the embryo in immediate contact with the soil water and 

 so tide it over the period required for the development of an absorbing 

 root surface. The coleorhiza is regarded as a protective organ of 

 the main root in the embryonic stage, but it is manifest that it also 

 later takes on an additional function. At first it serves as a substitute 

 for the root and subsequently supplements the function of this organ. 

 The coleorhiza appears not only before the root has elongated, but 

 it continues to function for a long period thereafter. Thus, the 

 coleorhiza hairs of Poa pratensis and Phleum pratense were found to 

 be normal and functioning thirty days after germination. 



Few organs of the embryo have received more attention or aroused 

 more divergent views than the epiblast. The behavior of this structure 

 would rather lead one to accept the contentions of Van Tieghem, 36 

 Schlickum 29 Celakovsky, 45 Worsdell, 37 Bruns, 2 Coulter 6-7 and others. 

 The results of their researches indicate that the coleoptile, scutellum 

 and epiblast are all parts of one structure, the cotyledon, and that 

 they represent, respectively, the ligule, lamina and auricles of the 

 vegetative leaf. The sheathing leaf base disappears, or at least is 



