502 Callivation of Tropceolums. 



allowed to become filthy, their organs of respiration become 

 stopped ; they turn languid, unhealthy, and subject to the 

 attacks of insects, which are more frequently the consequence 

 than the cause of disease. 



They should always be freely aired, which will cause a 

 sturdy growth and an equally profuse distribution of flower. 

 When the flowers begin to fade let them have less water, 

 and as the leaves change color place them out of doors and 

 keep them dry to mature the tubers ; they may then be turned 

 out of the pots and placed on a dry, airy shelf, there to re- 

 main until they again show symptoms of growth. 



The propagation of these plants may be effected either by 

 seeds or cuttings. When seeds can be obtained, they pro- 

 duce the most vigorous growing plants. These should be 

 sown as soon as ripe, in light soil, the pots well drained and 

 placed near the glass in the greenhouse. As the plants ap- 

 pear, put in a small stake to each, to which it will climb. 

 This should be allowed to remain after the stem decays, and 

 it will serve as a mark to indicate the place of the tuber. It 

 is well not to disturb them until they shoot forth a second 

 time, as some of the seeds may not vegetate until the second 

 year. If they thrive well they will flower the third year of 

 their growth. 



Cuttings of most of the species root readily if properly 

 attended to. For this purpose select the strongest of the 

 lateral shoots when about two inches long ; cut them out 

 with a small piece of the stem, and insert them in a well 

 prepared cutting pot. They will seldom recover if once 

 allowed to droop. Care must therefore be taken that their 

 juices are not exhausted by too much light or air. If placed 

 in a moderate bottom heat the formation of tubers will be 

 accelerated, otherwise they are apt to lapse into a state of 

 rest before this takes place. When the stems begin to decay, 

 they should be kept perfectly dry, but they need not be dis- 

 turbed untfl they have completed their second growth. 



Another method of propagating those that are most diffi- 

 cult to raise from cuttings, such as tricolorum and brachy- 

 ceras, is to place the tuber, when commencing its growth, 



