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- Dichotomous Key
- Poaceae
- Poaceae Group 10
- Paspalum
- Paspalum setaceum
Paspalum setaceum — slender beadgrass
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Facts
There are three varieties of slender beadgrass in New England. The most widespread (Paspalum setaceum var. muhlenbergii) is present in all New England states except Maine. Another (P. setaceum var. psammophilum) is found primarily on the coastal plain of Connecticut, Massachusetts and Rhode Island. The third (P. setaceum var. setaceum) is also found in Connecticut, Massachusetts and Rhode Island.
Habitat
Anthropogenic (man-made or disturbed habitats), forest edges, meadows and fields
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
- New England state
-
- Connecticut
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf blade width
- 1.5–10.2 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
- 1.4–2.5 mm
- Glume relative length
- one or both glumes are as long or longer than 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 ligule length
- 0.2–0.5 mm
-
Flowers
- Anther number
- 3
- Awn on glume
- the glume has no awn
- Bristles below spikelets
- no
- 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
- one or both glumes are as long or longer than all of the florets
- Glume veins
-
- 0
- 1
- 3
- 5
- 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 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 has pairs (or trios) of spikelets that are similar to each other in structure and size, with at least one of the spikelets on a stalk
- the inflorescence is branched and the branches all grow from the same side of the plant and look like spikes
- Lemma awn base
- NA
- Lemma awn coiled
- NA
- Lemma awn length
- 0 mm
- Lemma awn number
- the lemma has no awn
- Lemma awn orientation
- NA
- Lemma cross-section
- the lemma is flat or rounded if you cut across the midpoint
- Lemma surface
- the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)
- Lemma tip
- the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)
- Lemma vein number
-
- 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 no extension of the spikelet axis beyond the tip of the spikelet
- Spikelet length
- 1.4–2.5 mm
- Spikelets spiny
- the spikelets do not appear spiny
-
Leaves
- Leaf auricles
- the leaves do not have auricles
- Leaf blade hairs
- the leaf blade is hairy
- Leaf blade width
- 1.5–10.2 mm
- Leaf ligule length
- 0.2–0.5 mm
- Leaf ligule type
- the leaf ligule is in the form of a membrane
- 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 hairs
-
- there are hairs on the surface of the leaf sheath
- there are no hairs on the surface of the leaf sheath
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- edges of forests
- man-made or disturbed habitats
- meadows or fields
-
Stem, shoot, branch
- Stem orientation
-
- the stems are upright
- the stems trail along the ground or on other plants through most or all of their length
- Stem spacing
-
- the stems grow close together in compact clusters or tufts
- the stems grow singly or a few together (they may form diffuse colonies)
Wetland status
Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
In New England
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- present
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- unranked (S-rank: SNR)
var. muehlenbergii
- Vermont
- rare (S-rank: S2)
var. muhlenbergii
- Massachusetts
- widespread (S-rank: S5)
- New Hampshire
- uncommon (S-rank: S3), W (code: W)
var. psammophilum
- Connecticut
- historical (S-rank: SH), special concern, extirpated (code: SC*)
- Massachusetts
- rare to uncommon (S-rank: S2S3)
- Rhode Island
- extremely rare (S-rank: S1), concern (code: C)
var. setaceum
- Massachusetts
- uncommon (uncertain) (S-rank: S3?)
Subspecies and varieties
Variety psammophilum is known from CT, MA, RI and occurs primarily on the coastal plain. Variety muhlenbergii is known from CT, MA, NH, RI, VT. Variety setaceum is known from CT, MA, RI.
From Flora Novae Angliae dichotomous key
2. Paspalum setaceum Michx. N
slender beadgrass. 2a. Paspalum psammophilum Nash; 2b. Paspalum ciliatifolium Michx. var. muhlenbergii (Nash) Fern.; P. muhlenbergii Nash; P. pubescens Muhl. • CT, MA, NH, RI, VT. Sandy fields, roadsides, and forest edges.
1a. Plants prostrate to wide-spreading; leaf blades pubescent with short, soft hairs shorter than 1.5 mm … 2a. P. setaceum var. psammophilum (Nash) D. Banks
1b. Plants erect to spreading; leaf blades pubescent, at least in part, with stiffer hairs longer than 1.5 mm (shorter hairs may also be present)
2a. Spikelets 1.8–2.5 ×1.5–2 mm; lower lemmas usually with a midvein … 2b. P. setaceum var. muhlenbergii (Nash) D. Banks
2b. Spikelets 1.4–1.9 ×1.1–1.6 mm; lower lemmas usually without a midvein … 2c. P. setaceum var. setaceum
Variety psammophilum is known from CT, MA, RI and occurs primarily on the coastal plain. Variety muhlenbergii is known from CT, MA, NH, RI, VT. Variety setaceum is known from CT, MA, RI.
Native to North America?
Yes
Sometimes confused with
- Paspalum laeve:
- spikelets 2.3–3.3 mm long, solitary at each node, and ligules 1.5–3.8 mm long (vs. P. setaceum, with spikelets 1.4–2.5 mm long, paired at each node, and ligules 0.2–0.5 mm long).
Synonyms
- Paspalum psammophilum Nash