﻿BOTANICAL GAZETTE 



[JANUARY 



pathologist frequently finds the work with ornamental plants 

 unsatisfactory and complicated by physiological problems and 

 difficulties which make the returns uncertain. 



1. The growing of ornamental plants is of very great importance 

 and involves millions of dollars annually. The most casual observer 

 must be impressed by the large number of greenhouses in the 

 vicinity of large cities, the great quantities of cut flowers displayed 

 in city markets, and the fine plantings in public gardens and parks. 

 To these must be added the private conservatories and gardens. 



2. It is very evident that plant pathologists are not well in- 

 formed concerning the diseases of ornamental plants and therefore 

 cannot give as ready answers to the inquiries from the growers as 

 they can to the growers of other kinds of plants, and for reasons 

 stated in topic 3 find the study of diseases of ornamentals unsatis- 

 factory. Furthermore, pathologists usually have all they can 

 attend to in studying the diseases of fruits, vegetables, and field 

 crops. The growers of ornamentals have many empirical rules for 

 their work, some of which are very carefully guarded. However, 

 when we find them mistaking fungus spots on leaves and stems for 

 scale insects and treating their plants with insecticides when they 

 should be treated with fungicides, we begin to realize that studies 

 and publications along this line are very necessary. 



3. This work falls into two divisions, outdoor and indoor 

 plants. In the first of these we know very little beyond the 

 treatments for chrysanthemum rusts and mildews, and a very 

 few other diseases. The root diseases, which are carried back 

 and forth between the greenhouses and the outdoor plots and 

 which are frequently intensified by the fertilizers, present some of 

 the most profitable lines of research. These problems very natu- 

 rally blend to some extent into the seed bed and truck crop problems. 



The indoor problems are by far the most complicated and the 

 most difficult. Some of them are influenced by the character of the 

 fertilizers, and by very slight variations in temperature, humidity, 

 sunlight, and air currents. They are in many respects problems in 

 physiology rather than pathology. It also occurs that two related 

 varieties may require slightly different environmental conditions 

 to protect them from the same parasite. However, many of the 



