flatsedges

genus Cyperus

Member of sedges (family Cyperaceae)
grasses, sedges, cattails, and allies (order Poales)
monocots (class Liliopsida)
flowering plants (subphylum Angiospermae)

Except for old historical records and extremely rare examples that I don't expect to encounter, there are no other wild species of this genus in the bay area.

1 stem

purple nutsedge
Cyperus rotundus

flower bracts purple to red-brown
extremely rare at new near-coast addition to Purisima Creek

yellow nutsedge
Cyperus esculentus

flower bracts yellow-brown to dark-brown
rare

Generally > 1 stem

black flatsedge
Cyperus melanostachyus

2 stigmas

all others below have 3 stigmas

2-sided fruit

all others below have 3-sided fruit

rare

bearded flatsedge
Cyperus squarrosus

at least some flower bract tips distinctly outcurved, narrow-acute or bristle-like

all others below have flower bract tips that are neither distinctly outcurved nor bristle-like

extremely rare

umbrella papyrus
Cyperus alternifolius ssp. flabelliformis

no basal leaf blades

all others below have basal leaf blades

14–22 inflorescence bracts

all others below have 1–12 inflorescence bracts

rare

tall flatsedge
Cyperus eragrostis

fruit body ± as long as wide
common

redroot flatsedge
Cyperus erythrorhizos

fruit body 1.5–3 × longer than wide
flower bract 1.3–1.5 mm
fruit 0.7–1 mm
rare

fragrant flatsedge
Cyperus odoratus

fruit body 1.5–3 × longer than wide
flower bract 2–4 mm
fruit 1.5–2.4 mm
stem base not thickened
spikelet axis jointed at each bract
very rare

straw-colored flatsedge
Cyperus strigosus

fruit body 1.5–3 × longer than wide
flower bract 2–4 mm
fruit 1.5–2.4 mm
stem base thickened
spikelet axis continuous
extremely rare at Wilder Ranch near ocean

Toxicity of cyperus (Cyperus spp.):
4 – Ingestion of these plants, especially in large amounts, is expected to cause serious effects to the heart, liver, kidneys or brain. If ingested in any amount, call the poison center immediately.

2 observed taxons / 7 unobserved taxons / 1 key

Chris’s observations: 16 (10 are research grade)

Locations:

Bear Creek Redwoods OSP: 2
Lake Chabot RP: 2
Sweeney Ridge National Recreation Area: 2
Big Basin SP
El Corte de Madera OSP
Kauai, HI
Murray Ranch SP
Pescadero Creek CP
Pinnacles NP
Portola Redwoods SP
Stevens Creek CP
Wilder Ranch SP
Wunderlich CP

Months:

May: 1
Jun.: 1
Jul.: 6
Aug.: 2
Sep.: 1
Oct.: 2
Nov.: 3

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Taxon info: iNaturalist – Calflora – Jepson eFlora – FNA

Bay Area species: iNaturalist – Calflora