difficult te determine, but since there were no traces of emergent vegetatien 
at the center te indicate that the water had been shallew eneugh within the 
previous few years for it to have become established, the pethole was 
considered permanent. After years of extreme drought, this criterien prebably 
could net be used, since even those areas here classified as permanent might 
be choked with emergents. 
Potholes were classified as semipermanent if they ceuld be expected te 
go dry during the summer except in years of abnormally high rainfall. The 
criterion in this case was the presence ef a well-develeped stand ef emergent 
vegetation with less than 10 percent ef the area epen water. 
Temporary Waters are these With ne well-develeped emergent vegetatien, 
but which contained water in the spring am after heavy rains. 
Dugouts were small permanent water areas made during the dreught years 
for the purpese of watering stock when natural petheles were drying up, 
Those which had overflewed at the ends, so that their margins were ne lenger 
steep-sided, were classed as natural petheles of one of the above types. 
Vegetatien -- The original outline mapa of the potholes were taken inte 
the eTetd and the vegetation was sketched on them while notes were made on 
the relative abundance and density of the varieus species, 
Feur principal vegetation types were distinguished in the permanent and 
semipermanent potholes. There was a great deal ef everlap between them, and 
more or less arbitrary lines have been drawn for purposes of description 
and discussion. Plate III shows the distribution of all but the temperary 
waters. 
The Pothole Types 
Type Al -- The permanent sedge-whitetop potholes appeared rather barren 
at first glance. The border vegetatien was dominated by a mixture of 
whitetop grass (Scolochloa festucacea)and a large sedge (Carex sp.) about 
3% feet high usually growing separately in clumps at the edge of the open 
water and merging into a solid stand near and on the shore. 
Table 3 shows the species and eccurrence of the vegetation found in 
this type of pothole, listed in the erder of their abundance, The first 
column shows the percent occurrence of each species present. Thus, cattail 
( a latifelia) was found in 68 percent of these areas. The second column 
represents the average percentage of the vegetation sone occupied by the 
species, Thus, cattail occupied 3 percent of the area covered by emergent 
vegetation, The third column shews the average density at which the species 
grew in each pothole type. This has been rated subjectively from I (sparse) 
to III (dense). 
Frequently there were scattered clumps of cattail or hardstem bulrush 
(Scirpus acutus) at the edge of the open water, The only other commonly 
abundant species were lesser duckweed (Lemna minor) and star duckweed (L. 
trisulca). A mixture of spikerush (Eleocharis spp.) and rush (Juncus spp.) 
sometimes occurred as a ring on the drier side of the sedge-whitetop zene, 
but in most cases the sedge-whitetop merged directly into the more-moisture- 
tolerant weeds and grasses of the prairie, or with a willew zone. Some of 
these areas showed a distinct band of wild barley between the emergent 
vegetation and the prairie. 
