POT-PLANTS IN GREENHOUSES AND FRAMES 23 



first be well soaked in water. Unless this is done, the 

 material of which the pots are composed is so absorbent that 

 it may abstract so much moisture from the soil that the roots 

 are dried up. 



Fig. 



9. — Examining the roots of a Fern, infested with 

 the root-feeding mealy bug. 



When plants turn sickly, the cause may be obvious at a 

 glance. Insects may be seen on the leaves, or the nature of 

 the injury may clearly indicate that they are the culprits. The 

 leaves may be covered with dust, or with a film of oil from a 

 lamp or from recent painting ; or spots or other symptoms 

 may point to fungoid disease. On the other hand, the cause 



