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- Setaria parviflora
Setaria parviflora — knotroot foxtail
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Facts
Knotroot foxtail is native to much of North America, but at the northern limit of its range in New England. In our region it is an uncommon inhabitant of the margins of salt marshes and disturbed areas near the coast.
Habitat
Anthropogenic (man-made or disturbed habitats), marshes, wetland margins (edges of wetlands)
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
Found this plant? Take a photo and post a sighting.
Characteristics
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Massachusetts
- Rhode Island
- Leaf blade width
- 2–8 mm
- Inflorescence branches
-
- the flowers are attached to branches rather than to the main axis of the inflorescence
- there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
- Spikelet length
- 2–2.8 mm
- Glume relative length
- neither glume is quite as long as all of the florets
- Awn on glume
- the glume has no awn
- One or more florets
-
- there is more than one floret per spikelet
- there is one floret per spikelet
- Lemma awn length
- 0 mm
- Leaf sheath hair type
- there are no hairs on the surface of the leaf sheath
- Leaf ligule length
- 0.4–1.2 mm
- Anther length
- 1.2–1.6 mm
-
Flowers
- Anther length
- 1.2–1.6 mm
- Anther number
- Up to 3
- Awn on glume
- the glume has no awn
- Bristles below spikelets
- yes
- Floret lower bract texture
- the lemma is hard and firm
- Floret number
- 1–2
- Floret types within spikelet
-
- NA
- there are at least two distinct forms of florets within one spikelet
- Glume relative length
- neither glume is quite as long as all of the florets
- Glume shape
- the glume is flat or curved in cross-section
- Glume veins
-
- 3
- 5
- 7 or more
- Inflorescence arrangement
- the spikelets are uniform
- Inflorescence axis hairs
- the inflorescence axis is hairy but not rough or sand-papery feeling
- Inflorescence axis orientation
-
- the inflorescence axis is arched or curved outward
- the inflorescence axis is straight
- Inflorescence branches
-
- the flowers are attached to branches rather than to the main axis of the inflorescence
- there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
- Inflorescence crowding
- the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
- Inflorescence length
- 30–100 mm
- Inflorescence type (general)
-
- the inflorescence is a spike, or is spike-like, lacking obvious branches
- the spikelets are borne on stalks or on branches
- Inflorescence type (specific)
- the inflorescence is branched, and the branches do NOT both grow from the same side of the plant AND look like spikes
- Inforescence position
- the spikelets are mainly carried at the end of the stem
- Lemma awn base
- NA
- Lemma awn length
- 0 mm
- Lemma awn number
- the lemma has no awn
- Lemma cross-section
- the lemma is flat or rounded if you cut across the midpoint
- Lemma surface
- the surface of the lemma has wrinkles that are oriented across the lemma
- Lemma tip
- the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)
- Lemma vein number
-
- 1
- 3
- 5
- One or more florets
-
- there is more than one floret per spikelet
- there is one floret per spikelet
- Palea relative length
- palea is one half to fully as long as lemma
- Spikelet axis tip
- there is an extension of the spikelet axis beyond the tip of the spikelet
- Spikelet length
- 2–2.8 mm
- Spikelets spiny
- the spikelets do not appear spiny
-
Growth form
- Lifespan
- the plant lives more than two years
- Rhizomes
- yes
- Roots
- the plant has rhizomes (horizontal underground stem with roots growing from it)
-
Leaves
- Leaf auricles
- the leaves do not have auricles
- Leaf blade width
- 2–8 mm
- Leaf ligule length
- 0.4–1.2 mm
- Leaf ligule type
- the leaf ligule is in the form of fine hairs
- Leaf margin glands
- there are no glands along the edges of the leaf blade
- Leaf sheath closed around stem
- the margins of the leaf sheath are overlapping and not fused together except in the basal half (or less)
- Leaf sheath hair type
- there are no hairs on the surface of the leaf sheath
- Leaf sheath hairs
- there are no hairs on the surface of the leaf sheath
- Orientation of topmost leaf
- the flag leaf is held upright, or at less than a 45 degree angle out from the stem
-
Place
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Massachusetts
- Rhode Island
- Specific habitat
-
- edges of wetlands
- man-made or disturbed habitats
- marshes
-
Stem, shoot, branch
- Stem spacing
- the stems grow close together in compact clusters or tufts
Wetland status
Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)
In New England
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- present
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- uncommon (S-rank: S3), special concern (code: SC)
- Rhode Island
- extremely rare (S-rank: S1), concern (uncertain) (code: C*)
From Flora Novae Angliae dichotomous key
3. Setaria parviflora (Poir.) Kerguélen N
knotroot foxtail. Panicum geniculatum Lam.; Setaria geniculata (Lam.) Beauv. • CT, MA, RI. Borders of saline marshes, disturbed soil.
Native to North America?
Yes
Sometimes confused with
- Setaria pumila:
- plants annual from fibrous roots and axis of the inflorescence villous and/or hispid (vs. S. parviflora, with plants perennial from short, knotty rhizomes and axis of inflorescence scabrous-hispid).
Synonyms
- Panicum geniculatum Lam.
- Setaria geniculata (Lam.) Beauv.