132 PRACTICAL BOTANY 



Treat a section, in which one or more crystalloids are under 

 observation, with potash : the crystalloids will be seen to swell 

 and dissolve. 



Mount another section in alcohol or in glycerine, and, having 

 observed the crystalloids, irrigate with a saturated solution of 

 common salt : this also will dissolve the crystalloids. 



, GERMINATION. 



(A) Dicotyledons. 



(a) Examine seedlings of vHelianthus which have been 

 germinating for different periods from one day to one week, 

 and observe the following points in the process of germina- 

 tion : 



1. The internal parts of the fruit swell, and cause the brittle 

 pericarp to split longitudinally. 



2. The radicle protrudes, and curves downwards. 



3. The hypocotyledonary stem elongates, so that the pericarp 

 and seed-coat are carried upwards by the cotyledons, which 

 remain inclosed by them for a considerable time. 



4. The coats of the fruit fall from the cotyledons, which soon 

 turn green, and expand as assimilating leaves, with the plumule 

 seated between them. 



5. The plumule develops leaves, which expand in succession. 



6. The radicle has meanwhile elongated, and produced lateral 

 roots. 



Notice that when the young root is removed from the soil 

 many particles adhere to it, especially at some distance from 

 the apex : these are held by the root-hairs which attach them- 

 selves closely to the particles of soil. 



(b) With the above compare seedlings of Ricinus in various 

 stages of germination : in the main features the results are the 

 same, but note especially that the endosperm remains for a long 

 period in close connection with the cotyledons, and that as the 

 seedling grows that tissue loses its firmness and density, owing 

 to the abstraction of the nutritive substances stored in it, and 

 their transfer through the cotyledons to the seedling. 



