THE GARDEN BOOK OF CALIFOR NIA 



spines in clusters, and thread-like roots which attach them- 

 selves to the nearest support. Most of these have cream and 

 white blossoms, but that of Cereus rostratus is a beautiful 

 red. 



Decay at the roots or in the stem is about the only disease 

 cacti are subject to, and if it is remembered that they belong 

 to warm, dry countries, and therefore should be watered 

 with moderation and discretion this disease may be practi- 

 cally avoided. However, when struck by disease, use the 

 knife to remove the diseased portion, rubbing the cut with a 

 little finely pulverized charcoal or lime. I have noticed 

 symptoms of approaching disease in favorite plants once or 

 twice, a "yellow tinge of countenance" or a disposition to 

 produce spines and no blossoms. Such a plant I have 

 deliberately torn up by the roots from its pot, or the garden 

 bed, as the case might be, and laid it on the shelf to dry a 

 few days. The "rest cure" will do wonders for an 

 Echinocactus or Mamillaria, and upon replanting they will 

 speedily show vigor, and blossom freely. 



California house plants are more liable to attacks from 

 insect pests than those grown in the open air. My own col- 

 lections have at times been attacked by the mealy bug, and 

 by various forms of scale. When either one first appears it 

 may be removed with a sharp-pointed stick, or by syringing. 

 A vigorous washing with syringe or garden hose will some- 

 times suffice, but in the case of the mealy bug, which secretes 

 itself among the spines, and resembles a bunch of white 

 cotton more than anything else, I have found a kerosene 



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