326 PROCEEDINGS OF THE ACADEMY OF [April, 



THE MUTATION OF HIBISCUS MOSCHEUTOS L. 



BY JOHN W. HARSHBERGER. 



The views of De Vries on the origin of species by mutation rest upon 

 the result of seventeen years of experimentation. This botanist holds 

 that new elementary species arise suddenly without transition or inter- 

 mediate forms, and that these species are constant from the moment 

 of their origin and show no resemblance in their characters to the indi- 

 vidual variations exhibited by the parent type. De Vries believes that 

 mutability occurs only at certain periods, and a species might continue 

 in existence indefinitely without giving rise to new forms. This 

 succinctly states the position of the illustrious Dutch botanist upon 

 the origin of species. 



The observations here recorded are given with the hope that they 

 may add somewhat to the discussion of the problems opened up by the 

 work of De Vries. 



Hibiscus moscheutos L., the swamp rose mallow, is found abundantly 

 at Sea Side Park, N. J., where it covers acres of the salt marshes. Here, 

 undisturbed by man, the plants offer special advantages for study. It 

 was noticed that no two plants growing in the open meadow were ex- 

 actly alike. Consequently, a study was instituted to determine, if pos- 

 sible, the character of the divergences. All of the plants studied grew 

 practically under the same conditions, although in certain places the soil 

 of the meadow was wetter than in others. So as to make the observa- 

 tions continuous for a number of years and upon the same plants, 

 stakes were driven into the marsh at the base of each plant collected 

 and studied. These stakes were marked by cutting Roman numerals 

 into a planed-off portion at the top. 



The plants numbered I-XII grew in a wet portion of the meadow 

 near an open slue. Those designated as XIII to XXV grew in the 

 drier portions of the meadow, excepting XXV, which grew beside a 

 hole filled throughout the season with water. Specimens of these 

 plants were submitted to Prof. De Vries, who pronounced upon them 

 as follows, extracted from a letter dated November 26, 1902: "I have 

 studied the Hibiscus moscheutos with the greatest interest, and beheve, 

 with you, that you have hit at cases of mutation parallel to that of 



