76 



The foregoing- notes, incomplete as they are (heing based on 

 only about eleven hours of travel), may be useful to those who 

 may hereafter stud}^ Louisiana vegetation more intensively ; and 

 they illustrate a method of making observations in comfort in an 

 interesting area where mosquitoes and scarcity of water might 

 make traveling on foot rather disagreeable in summer. 



THE VALUE OF NUTRIENT SOLUTIONS AS CULTURE 

 MEDIA FOR FERN PROTHALLIA* 



By Elizabeth Dorothy Wuist Brown 



The value of nutrient solutions as culture media for growing 

 fern prothallia under experimental conditions being so well 

 known, it is the purpose of this paper to emphasize the value of 

 these solutions for growing prothallia for class use. Excellent 

 cultures may be obtained by using soil, peat and various other 

 media, but it has been the writer's experience that the work is 

 greatly simplified by the use of the nutrient solution. For after 

 the solutions have been prepared and the cultures set up under 

 the best light conditions available, little attention need be paid to 

 them. 



Aside from the time-saving element in caring for the cultures 

 is the advantage of having an abundance of material in various 

 stages of development always at hand. In this way it is possible 

 for the student to follow the development of the prothallia from 

 the one-cell stage to the adult form bearing antheridia, arche- 

 gonia and sporophytes. This may be accomphshed by varying 

 the time of sowing the spores in the different cultures. It is well 

 to learn the length of time required for the germination of the 

 spores and the development of the prothallia of the particular 

 species used before setting up the cultures for class use. The 

 time of germination varies somewhat in different species, being 

 more rapid in the spores containing chlorophyll. 



The following solutions, Beijerinck's, Borner and Lucanus's, 

 Knop's, Prantl's and Sachs's, proved favorable for the germina- 



* Contribution from the Osborn Botanical Laboratory. 



