Most of these potholes were ringed by a dense zone of cattail merging 
into a zone of spikerushes, The submerged vegetation was dominated by water 
milfoil, which partially covered the surface. Pondweed (Potamogeton spp.), 
star duckweed, and a trace of lesser duckweed were also present. The distri- 
bution of plant species in this type is illustrated in Plate V, a cover map 
of pothole 14. 
There Was a more or less continuous trend from the pure sedge-whitetop 
to the pure cattail areas and the borderline between types Al and A2 was 
extrenely vague. However, since these different types varied greatly in the 
amount of use they received by waterfowl, it was deemed necessary to make an 
arbitrary division into two types for purposes of study. 
e A3 <= Permanent hardstem-bulrush potholes showed a marked decrease 
in the importance of duckweeds and an increase in other submerged aquatics 
including pondweeds and green algae (Table 5). The surface of three of these 
areas became choked with these plants by late summer, The most prominent 
emergent was hardstem bulrush which made up at least 30 percent of this zone. 
Cattail was also abundant, growing as a ring outside the hardstem bulrush 
and mixed with softstem bulrush (Scirpus validus) and/or whitetop. Cattail 
islands were intermingled with islands of hardstem bulrush. Each pothole 
of this type had a well-developed zone of spikerush and rush, which included 
whitetop in two cases, and was surrounded by a ring of wild barley, 
The deepest of these potholes (No. 3), where the hardstem bulrush grew 
in 1 to 3 feet of water, had a sparser growth of hardstem bulrush than did 
the others of this type. A band of whitetop had become established on the 
north end and made up all the emergent vegetation of that shore. Some of 
these potholes contained a large amount of green algae which choked the 
surface by late summer. Others contained water milfoil in large quantities 
which could be seen covering the surface, A mixture of cattail, rush, spike- 
rush, and sparse whitetop formed the shallow-water and moist-soil vegetation 
of two of these potholes (Nos. 2 and 5). A well-developed stand of whitetop 
grew in 2 feet of water in pothole No. 1, in which hardstem bulrush was the 
most prominent species, This stand grew ali along one shore for a distance of 
about 200 yards in deeper water than the bulrush. Plate VI indicates the 
relations of the zones of vegetation in pothole No. 2. As can be seen, 
these potholes were highly variable in the density and composition of their 
vegetation. However, there seemed to be little relationship between these 
and either the cattail or the sedge-whitetop potholes. 
Al, -- These potholes with zones of emergents intermixed or denuded 
had in common a conspicuous lack of zonation of the emergent vegetation as 
shown in Plate VII. 
As shown in Table 6, star duckweed was conspicuous in this type as was 
water milfoil which had choked much of the surface of three of these potholes 
by early August and was prominent in three others. The emergent vegetation 
showed no single dominant species common to the type although there. were 
usually clumps of cattail, hardstem bulrush, and softstem bulrush interspersed 
with slough grass (Beckmannia syzigachne) and other species in lesser amounts. 
The ring of rush and spikerush surrounding these potholes was conspicuous. 
Whitetop and sedge, which occurred often, were found mainly on those portions 
of the margins which were protected from grazing. Wild barley was 
conspicuous surrounding the zone of emergents. 
