MAIZE GERMINATION 227 



(B) Monocotyledons. 



I. Comparing plants of Maize which have been 

 germinating for different periods, the following facts in 

 the history of germination may be observed : 



1. The fruit swells. 



2. The outer coat ruptures opposite the apex of the 

 radicle, which soon protrudes, bursting through the 

 coleorhiza also, which appears as an irregular ring 

 round the base of the young root. Since the coleorhiza 

 is thus burst through by the young, root, it is clear that 

 the epidermis of the shoot is not continuous with the 

 piliferous layer of the root. 



3. The rupture of the coat extends upwards to the 

 point opposite the apical bud, which also emerges. 



4. The root elongates, and forms lateral roots : other 

 lateral roots (usually two) burst out above the insertion 

 of the scutellum : these soon equal the primary root in 

 length, hence there is no well marked tap-root. 



5. Leaves of the plumule unfold, and gradually turn 

 green : the leaf inserted lowest, which was the outermost 

 of those composing the plumule, remains small and 

 develops no expanded lamina : this is the cotyledon, 

 according to Hofmeister and other writers. 



II. From a young plant with leaves about three 

 inches long, cut longitudinal sections so as to traverse 

 the whole fruit and the contiguous part of the seedling 

 in a median plane : mount in water, and irrigate with 

 solution of iodine. Observe 



1. That in the neighbourhood of the surface of the 



Q 2 



