THE SEED 7 



force its way through the soil in which the seed is 

 sown. 



Observation of germinating kidney beans shows that 

 the root, on its emergence from the seed, does not grow 

 straight down into the soil, but bends in an arch near the 

 seed and then grows straight downwards. This arch is 

 generally the first thing which makes its appearance 

 above the soil, and, from its form and structure, is well 

 fitted to thrust aside the particles of earth. After the 

 arch is formed, the young plant is firmly anchored in the 

 soil by means of the root. 



The arch has now another duty to perform ; the 

 seed-coat still covers the cotyledons and the plumule ; 

 these must be liberated. The seed-coat is held fast by 

 the soil sticking to it ; the arch continues to grow in an 

 upward direction, and, as a result, the cotyledons are 

 withdrawn from the seed-coat, much in the same manner 

 as a hand is drawn out of a glove. When this is done, 

 the arch straightens out and the plant grows into an 

 upright position. 



In order that the seed-Coat may be held firmly by the 

 soil and not be drawn out by the plant's movements 

 during germination, seeds are frequently provided with 

 projections, spines or hairs, which, becoming attached to 

 the soil, afford the necessary firmness of hold. In some 

 cases, for instance, linseed (flax) and cress, the seeds are 

 provided with a seed-coat which becomes mucilaginous 

 and sticky when wet, thus effecting the same purpose. 



On looking over a plot where a number of beans are 

 germinating, it may often be noted that some of the 

 seeds have not been able to rid themselves of their seed- 



