80 STUDIES IN THE VEGETATION OF THE STATE 



of the prairie on which the formational work was conducted. 

 Mr. Frank Zimmerer has rendered invaluable assistance in 

 photography and map-finishing in water colors, and also 

 along other lines. 



Throughout this treatise, the metric system of measures, 

 the Fahrenheit thermometer scale, and the nomenclature 

 based upon Britton and Brown's "Illustrated Flora" are 

 used. The author-citation is not considered imperative here, 

 and accordingly is omitted. 



Before any work of importance can be accomplished in 

 phytogeography, the physiography of the region as well as tha 

 flora must be adequately in hand. This is especially empha- 

 sized in the study of the formation, where it will be discussed 

 to some extent. The work of becoming acquainted with the 

 flora and the physiography of the country about Nebraska 

 City was begun in the autumn of 1897 and continued through- 

 out the followin*? year. During this time, also, a complete col- 

 lection of the plants was made and deposited with the botan- 

 ical department of the University of Nebraska. The pheno- 

 logical notes taken during this year were not considered 

 extensive enough to be of importance; this leaves the pheno- 

 logical records for 1899 and 1900, which were made as ac- 

 curate and complete as conditions would permit. 



The more important lines of investigation, with brief ex- 

 planatory notes, are here given : 

 I. Physical factors. 



1. Physical data consisting of, 



a. Soil temperature at a depth of ten centimeters. 

 6. Psychrometer readings (wet and dry bulb ther- 

 mometers) at surface of ground and one meter 

 abova 



c. Meteorological conditions as to amount and di- 



rection of wind, amount and seasonal distri- 

 bution of precipitation and sky conditions, 

 whether clear, overcast, or cloudy. 



d. Determination of physical 'water-content. 



