76 BULLETIN 1301, U. S. DEPARTMENT OF AGRICULTURE 
A brief discussion of each method and its results follows. The term 
‘“quadrat’’ in this discussion; unless otherwise specified, refers to an 
area of ground 1 meter (39.37 inches) square. 
Mapped quadrats.—In these quadrats, all species of plants are 
indicated on a chart drawn to scale. Single plants are designated by 
symbols, and plants that grow in bunches or mats are drawn in out- 
line and designated. Maps were made in the four continuously 
grazed pastures in 1915. The same quadrats have been mapped 
since that time. These quadrats are located in the open pastures 
and are therefore subjected to grazing. The mapped quadrats serve 
as permanent records of the composition of the vegetation. They 
show the relationship of the different species of plants, especially 
those that grow in mats (as blue grama grass), and bunches (as 
western needle grass). They show something of the effects of graz- 
Fic. 10—Native vegetation in the 30-acre pasture at the Northern Great Plains Field Station on 
July 15, 1922. The white plants are Artemisia frigida 
ing on different species. While maps have been made to show ali 
species in the quadrats, during recent years the maps have been drawn 
to show only blue grama and western needle grasses. These are the 
most important grazing grasses, and it is difficult to keep a record of 
them any other way. The quadrats mapped in 1922 indicate that 
western neecle grass has been reduced by the severe grazing in the 
30-acre pasture. 
List quadrats —The records of these quadrats are made by counting 
and recording the number of individual plants of species that grow 
singly or in distinct bunches. It is possible to keep such records on 
a comparatively large number of quadrats extending over the pastures. 
The lst-quadrat records made in 1922 in the overgrazed 30-acre 
pasture show that Artemisia frigida had increased until it was from 
two to three times as thick as in any of the other pastures. 
