DEPARTMENT OF BOTANICAL RESEARCH. 67 



Alterations Induced by Ovarial Treatments of Plants, by D. T. MacDougal. 



The extension of the work upon this subject has been wholly taken 

 up with the cultivation of the second and third generations of the 

 variants or mutants which were secured by the original treatments. 

 In addition to the new forms which have resulted from this method, 

 an additional derivative of a Scrophularia has now been secured. 

 The species is a native of the region in which the montane plantation 

 is situated and forms one of the suite of species under experimenta- 

 tion in the various climatic complexes. Some of the seeds, matured 

 in an ovary into which potassium iodide had been injected, pro- 

 duced plants in which the purplish color of the flower of the parental 

 stock was replaced by a cream white, with other morphological and 

 physiological departures. This material is now being carried into 

 the succeeding generation. 



It has remained for Col. R. H. Firth, of the Royal Army Medical 

 Corps of Great Britain, to duplicate these results in obtaining 

 atypic forms by ovarial treatments of plants (Firth, R. H., Jour. 

 Royal Med. Corps, 16, pp. 497-514, 1911). Colonel Firth culti- 

 vated a number of species of Onagracese in soils to which various 

 substances had been added and in this waj^ saw new forms appear. 

 Then injections into the ovaries of Oenothera odorata {Raimannia 

 odoraia), Epilobiwn roseum, and other species resulted in atypic 

 derivatives. Not much success w^as attained in the cultures of the 

 derived forms at Simla, East India, where the work was performed. 

 Dr. Firth intimates that the induction of forms by ovarial treatment 

 is most easily secured in plants subjected to unusual conditions of 

 cultivation or nourishment, which would support the suggestion 

 mentioned above to the effect that there is no direct relation between 

 the nature of the inciting agent and of the mutations induced. It 

 is of interest to note that Dr. Firth induced mutation in Raimannia 

 odorata {Oenothera odorata), in which the discovery of the method 

 was originally made by Dr. MacDougal in 1905. 



Miss Elizabeth Schiem^nn, in testing the excitation action of 

 various substances upon the common black mold (Aspergillus niger), 

 used potassium dichromate, copper carbonate, zinc sulphate, mag- 

 nesium oxide, and potassium chlorate, which were simply added to 

 the culture solution of the mold. Two atypic forms of mold were 

 seen to originate in the cultures to which potassium dichromate had 

 been added — ^one with brownish conidia was named A. fuscus and 

 was carried through 40 generations without change; a second, to be 

 known as A. cinnamonea, was characterized by conidia colorless at 

 first, which gradually change to sandy, then to cinnamon in color. 

 This form was followed through 34 generations. Other forms, known 

 as A. niger altipes and A. proteus, appeared in cultures kept at 

 unusually high temperatures. 



