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 261PRELIMINARY REPORTS 0-N THE FLORA OF WISCONSIN 
NO. 66. CYPERACEAE Il—SEDGE FAMILY II. 
The Genus Cyperus—The Umbrella Sedges 
Brian G. Marcks 
University Wisconsin—Madison 
 Cyperus, a vast genus of upwards of 700 species chiefly distributed in warm
temperate and tropical regions of the world, 
- is distinguished from other Cyperaceae by having, in combination, strictly
2-ranked (distichous) scales and terminal umbellate inflorescences or heads.
Since the group is technically difficult, examples of inflorescences and
their parts have been illustrated in Fig. 1 to aid in the un-derstanding
of some of the terminology used in this report. The Wisconsin species flower
from midsummer to early fall and occur in dry exposed sandy areas or in various
wetland habitats, such as marshes and bogs, swales and low fields, ditches,
and lakeshores, riverbanks and streamsides. Several of our species are notable
for their widespread distribution. Cyperus aristatus, C. esculentus and C.
odoratus are semi-cosmopolitan in tropical and temperate regions, while C.
Engelm-annii is widely distributed in the New World. Cyperus strigosus and
C. esculentus tend to become weedy in low fields. Phenotypic dwarfing is
common and particularly noticeable in depauperate specimens of the ' taller
wetland species, including C. strigosus, C. erythrorhizos, C. Engelmannii
and C. odoratus. 
 The present paper revises Greene's (1953) preliminary partial treatment
of Cyperaceae in Wisconsin, including the genus Cyp-erus. Distribution maps
are based on specimens in the herbaria of the University of Wisconsin, Madison
(WIS), University of Wisconsin 
—Milwaukee (UWM), Milwaukee Public Museum (MIL), University of
Minnesota
(MIN), Field Museum of Natural History (F), Wisconsin State University—Oshkosh
(WSO), Wisconsin State University—Stevens Point (WSP), and Northland
College, Ashland, Wisconsin (NC). Grateful acknowledgement is -due to the
curators of the above herbaria for loans of specimens. The results of my
master's and doctoral dissertations, population studies of Cyperus section
LAXIGLUMI in the United States (Marcks, 1967, 1972) have been freely incorporated.
- 
 Map dots represent exact locations. The map inset numbers record flowering
and fruiting dates as determined from specimens 
housed at the University of Wisconsin, Madison (WIS). Plants in