emergent
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Wetland and Aquatic Plants of Oklahoma

Interactive Keys: Emergent

Grasslike

Sedges (Cyperaceae)

4. Flatsedges or umbrella sedges (Cyperus spp.)
   
          a. Seeds (achenes) round; flowers two stigmas
          b. Seeds (achenes) three angles; flowers with three stigmas
               i. spikelets in dense heads
              ii. spikelets not in dense heads, inflorescence long and string-like

Seeds (achenes) round and lense shaped (lenticular); flowers with two stigmas

Yellow flatsedge (Cyperus flavescens L.) 
Native annual.
                                                                                                                                                           Click thumbnail to enlarge

Cyperus flavescens map                              Cyperus flavescens

NWI status: OBL
       
Seeds (achenes) three-angled; flowers with three stigmas

Spikelets in dense heads

Bearded flatsedge (Cyperus squarrosus L.) 
Native annual.

Cyperus squarrosus map                                Cyperus squarrosus

Note: The tips of the scales are strongly recurved. This is a small plant that grows in drawdown areas along lake shorelines.

NWI status: OBL

Marsh flatsedge (Cyperus pseudovegetus Steud.)
Native perennial.

Cyperus pseudovegetus map                                 Cyperus pseudovegetus

Note: Similar in appearance to breaded flatsedge, but much taller ans lacking recurved scales.

NWI status: FACW

Spikelets not in dense heads; inflorescence long and string-like

Tapertip flatsedge (Cyperus acuminatus Torr. & Hook. ex Torr.) 
Native perennial.

Cyperus acuminatus map                              Cyperus acuminatus

NWI status: OBL

Poorland flatsedge (Cyperus compressus L.) 
Native annual.

Cyperus compressus map                               Cyperus compressus

NWI status:  FACW 

Variable flatsedge (Cyperus difformis L.) 
Introduced annual.

                                                                                                                         Cyperus difformis

Note: A serious pest of rice and corn fields in Asia.

NWI status: OBL  

Redroot flatsedge (Cyperus erythrorhizos Muhl.) 
Native perennial.

Cyperus erythrorhizos map                              Cyperus erythrorhizos

Note: A very large and robust plant.  One of the most common flatsedges in Oklahoma.

NWI status: OBL  

Ricefield flatsedge (Cyperus iria L.) 
Introduced annual.

Cyperus iria map                               Cyperus iria

Note: This species is considered one of the World’s worst weeds.  It can profoundly affect rice cultivation.  Probably introduce to the United States in the early 19th century from Asia.

NWI status: FACW

Fragrant flatsedge (Cyperus odoratus L.) 
Native annual.

Cyperus odoratus map                              Cyperus odoratus

NWI status: FACW

Manyspike flatsedge (Cyperus polystachyos Rottb.) 
Native perennial.

Cyperus polystachyos map                                Cyperus polystachyos

NWI status: FACW

Strawcolored flatsedge (Cyperus strigosus L. )  
Native Perennial.

Cyperus strigosus map                               Cyperus strigosus

Note: A very large and robust plant.  One of the most common flatsedges in Oklahoma.

NWI status: FACW


 
 

Last update: 2/23/04
Comments to : Bruce Hoagland

bhoagland@ou.edu

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