136 



ILLINOIS ACADEMY OF SCIENCE 



TABLE II. 

 GERMINATION RECORD TURKISH RED WHEAT 

 Theoretical temperatures calculated by formula: T=a-b log Z. 

 Notation: T=:Temperature, Z=Time in minutes, a and b are 

 constants. 



Value found for a — 98.88. Value found for b — 11.78. 



♦Data from White's Experiment. 

 417, 1909. 



Proc. Royal Soc. London, 81, 



PECULIAR EXAMPLES OF PLANT DISTRIBUTION 

 A PROBLEM IN PHYTO-GEOGRAPHY 



H. S. PEPOON, LAKE VIEW HIGH SCHOOL 

 ABSTRACT 



Based upon the collection of 1800 species in the Chicago 

 area, 1000 species in Fulton county, and 900 species in the 

 driftless area of Jo Daviess county, the author cites numerous 

 examples of peculiar or unique distribution of plant species, 

 many of the examples being "extra limited" as far as the 

 printed record presents the assigned localities. 



He endeavors to group these examples under four main 

 causative agencies that may be tabulated in the order of their 

 increasingly greater numbers of representatives, as follows : 



a. Aboriginal plantings. 



b. Vestigial forms of glaciated times. 



c. Extension outpost forms. 



d. Survivals of destruction by human agency. 



Some 50 species are named in the discussion and the author 

 invitfes friendly criticism and further enumeration of ex- 

 amples. 



