LETTER IV 



Growth of Plants in Spring Endogens and Exogens The Loop 

 System The Spike System Effect of Light in retarding 

 growth Protection afforded by the drooping of blooms 

 Bees Robins Ewelme. 



20th March. 1886. 



DEAR MARCO Whilst we poor artists are 

 all struggling with our pictures, finishing and 

 getting them ready for the Exhibition, all the 

 little seeds and plants are bestirring them- 

 selves, much exercised as to the getting out 

 of their winter quarters beneath the ground, 

 and struggling to reach the upper air. 

 Warmth and light are the chief motive 

 powers in all cases, though there is con- 

 siderable variety in the modes of operation. 

 Plants are divided by botanists into two 

 principal classes : Exogenous and Endogen- 

 ous. Endogens, at least as far as we are 



