8 BULLETIN 883, U. S. DEPARTMENT OF AGRICULTURE. 
SCOPE OF THE EXPERIMENTS. 
The flax studies at Mandan in the years 1914, 1915, and 1916 
consisted of plat and nursery-row experiments with flax varieties, 
selections, hybrids, and new introductions and experiments with 
different dates and rates of seeding. Experiments with continuous 
cropping also were carried on, but these do not come within the scope 
of the present paper. In 1914 there were 44 plats and 217 nursery 
rows. A change in the size and arrangement of' plats and rows in 
1915 and additional studies increased these to 98 plats and 877 rows, 
while in 1916 a total of 148 plats and 2,090 nursery rows was included 
in the experiments. For the three years, 290 plats and 3,184 nursery 
rows were devoted to experiments with flax. 
In addition to the agronomic studies, samples of seed from the 
varietal experiments in plats and from some of the varieties grown 
in nursery rows were analyzed for their oil content and the nature of 
the oils produced. 1 
EXPERIMENTAL METHODS. 
The experiments with flax at Mandan were conducted with the 
following aims in view: (1) To determine the varieties best adapted 
to the semiarid conditions prevailing in the northern Great Plains 
area; (2) to obtain, through new importations, pure-line selection of 
superior adapted varieties, and the crossing of different varieties, 
strains with higher yielding possibilities, more resistant to disease, 
and with distinctive characters which would better enable purchasers 
and growers to insure against admixture and the substitution of 
inferior varieties; (3) to study certain problems in the inheritance of 
different characters of the flax plant; (4) to classify the cultivated 
flax varieties which are grown commercially for seed; and (5) to deter- 
mine the best cultural practices for the area, including rates and dates 
of seeding. 
Such a diversity of aims called for considerable variation in the 
size and arrangement of the plats and nursery rows. Occasionally, 
first-generation hybrids were grown in the greenhouse at Arlington 
Farm, near Washington, D. C, to save a year's time, but otherwise 
all experiments were conducted in the field. In 1916, a hail screen 
was provided for some of the hybrid material, but its use was not 
found practicable from the cultural point of view. Agronomic notes 
were taken on the varieties grown in plats and nursery, while more 
technical observations have been necessary hi the breeding and 
classification studies. 
The results of experiments in breeding and selection are not pre- 
sented herein. Those experiments were begun in 1914 and have not 
iThe chemical analyses reported in tins bulletin were obtained from studies conducted in cooperation 
with the Office of Drug. Poisonous, and Oil Plant Investigations. The writer wishes to express his 
thanks to Mr. Frank Rabak, of that office, under whose direct supervision the analyses were made. 
