Carex species:
The inflorescence is composed of tiny flowers that lack petals, they look like tiny seeds and are called perigynia, protruding out of the top of the perigynia are the stigmas (which are easily seen early in the season), the number of stigmas vary and can be helpful and important in identification.
C aquatilis (OBL)
lowest bracts: equals or exceeds inflorescence
Terminal spike: upright, staminate
Lateral spike: pistillate, sessile
Stigmas: 2
Perigynia Color: pale brown, greenish-yellow
Other: grow singly or tufted
C limosa (OBL)
lowest bracts: may not pass inflorescence
Terminal spike: upright, staminate
Lateral spike: peduncled, pistillate
Stigmas:3
Perigynia Color: green to straw colored
Other: reddish to yellowish-brown spikes
C livida (OBL)
lowest bracts: equals or exceeds inflorescence
Terminal spike: upright, staminate
Lateral spike: sessile or slightly removed, pistillate
Stigmas: 3
Perigynia Color:pale glaucous-green
Other: spikes are yellow green
C lyngbei (OBL)
lowest bracts: usually extends past inflorescence
Terminal spike: drooping, 2-3 staminate
Lateral spike: dropping, especially lower spikes, pistillate or may be staminate at the top
Stigmas: 2
Perigynia Color: yellow-brown to brown
Other: spikes on long peduncles, perigynia are yellow-brown to brown
C mertensii (FACW)
lowest bracts: almost always exceeds inflorescence
Terminal spike: drooping, pistillate above staminate, sometimes all staminate
Lateral spike: pistillate or with a few staminate at the base
Stigmas: 3
Perigynia Color: light green to pale yellow, becoming reddish at the ends
Other: spikes are club shaped, crowded and drooping
C podocarpa (FAC)
lowest bracts: shorter than or exceeding inflorescence
Terminal spike: 1-2, upright, staminate
Lateral spike: 1-3, pendant on peduncles, pistillate
Stigmas: 3
Perigynia Color: brown, to purplish- brown
Other: spikes are spreading or pendent
C rotundata (OBL)
lowest bracts: leaf like, may exceed inflorescence
Terminal spike: long, staminate
Lateral spike: 2, pistillate, no or short peduncle, upright
Stigmas: 3
Perigynia Color: shiny chestnut brown to straw colored, purplish black when mature
Other: inflorescence is upright
C utriculata = C rhyncophysa (OBL)
lowest bracts: exceeding inflorescence
Terminal spike: 2-4 staminate
Lateral spike: 2-5 upright, pistillate
Stigmas: 3
Perigynia Color: yellowish-green becoming straw colored or reddish purple
Other: 2 short teeth at beack apex
** C rostrata
always found in flooded areas with standing water, blades are glaucous green and u-shaped.