The genus Cyperus of Renfrew County:
A comparative study

By Grant A. Bickel, 2020

Cyperus diandrus Torrey, Low-umbrella flatsedge

Cyperus diandrus is uncommon in Renfrew County. It is found on shorelines. While it resembles C. bipartitus, it is easily distinguished by the color pattern on the floral scales and its persistent stigmas. C. diandrus seems to favor more calcareous wetlands and does not tolerate disturbance.

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Spikelets, achenes and scales of Cyperus diandrus

Figure 1. Spikelets, achenes and scales
Inflorescence of Cyperus diandrus

Figure 2. Inflorescence
An occurrence map of Cyperus diandrus in Renfrew County

Figure 3. Occurence map for Renfrew County and surrounding area.
Accession records for specimens from Renfrew County
Accession # Collector Date
CAN 468020 S.J. Darbyshire 1981-August-03
DAO 329797 S. Hay & C. Morisset 1981-August-26
CAN 437353 H.L. Dickson & H. Simpson 1977-August-25
CAN 531257 H. Simpson 1977-August-18
CAN 570126 M.I. Moore & W. Cooke 1971-September-10
CAN 570125 M.I. Moore 1970-September-27
DAO 245743 W.G. Dore 1960-August-23