STUDIES OF LOCALIZED STAGES IN SOME 

 PLANTS OF THE BOTANIC GARDENS 

 OF HARVARD UNIVERSITY. 

 JOSEPH A. CUSHMAN. 

 In animals and plants interesting stages occur at certain parts 

 throughout the life of the individual. These are expressed in 

 Jackson's law, "Throughout the life of the individual, stages 

 may be found in localized parts, which are similar to stages 

 found in the young, and the equivalents of which are to be 

 sought in the adults of ancestral groups." In a preceding paper 

 the author has described such localized stages in some New Eng- 

 land plants. In the present paper the same line of investigation 

 has been extended to certain exotic plants which have been 

 recently studied. Jackson showed that such localized stages 

 occur in organisms at very definite areas and under definite con- 

 ditions of growth. This view is corroborated by the present 

 study. 



My thanks are due to Prof. G. L. Goodale and Dr. E. W. Olive 

 for supervising my work, to Mr. Cameron for opportunities to 

 study a great number of seedlings in the greenhouses and for the 

 care of those under observation, and to Dr. Jackson for reading 

 this paper and for many helpful suggestions. 



The following examples show the various (Vvg\ 

 ideas here intended to be brought out in the \/^' 

 line of localized stages in development. 



Astragalus adsurgens Pall. Figs. 1-5. 

 This herbaceous plant, a native of Siberia, 

 shows in its early spring growth localized 

 stages in development. The leaves are com- 

 pound and so the differential characters are 

 more easily and definitely seen than in many 

 plants. Seedlings (Fig. 1) were obtained 

 beneath the adult plants which were at that 

 time — April — just appearing. The cotyle- 

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