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- Dactyloctenium radulans
Dactyloctenium radulans — button grass
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Facts
Button grass is native to Australia, and a rare visitor to North America, with a few widely scattered records, including the New England records from dump sites of nineteenth-century wool-carding factories in Massachusetts.
Habitat
Anthropogenic (man-made or disturbed habitats)
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.
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Characteristics
- Habitat
- terrestrial
- New England state
- Massachusetts
- Leaf blade width
- 3–4 mm
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Spikelet length
- 3.5–5 mm
- Glume relative length
- neither glume is quite as long as all of the florets
- Awn on glume
-
- the glume has an awn
- the glume has no awn
- One or more florets
- there is more than one floret per spikelet
- Lemma awn length
- Up to 1 mm
- Leaf sheath hair type
- there are hairs on the surface of the leaf sheath, and some of the hairs have blisters at their bases
- Leaf ligule length
- Up to 1 mm
-
Flowers
- Anther number
- 3
- Awn on glume
-
- the glume has an awn
- the glume has no awn
- Glume awn length
- At least 0 mm
- Glume relative length
- neither glume is quite as long as all of the florets
- Glume veins
- 1
- Inflorescence axis orientation
- the inflorescence axis is straight
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Inflorescence crowding
- the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
- Inflorescence length
- Up to 15 mm
- Inflorescence type (general)
- the spikelets are borne on stalks or on branches
- Inflorescence type (specific)
- the inflorescence is branched and the branches all 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
- the awn is attached right at the tip of the lemma
- Lemma awn length
- Up to 1 mm
- Lemma awn number
- the lemma has one awn on it
- Lemma cross-section
- the lemma is V-shaped if you cut across the midpoint
- Lemma surface
- the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)
- Lemma vein number
-
- 1
- 3
- One or more florets
- there is more than 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
- 3.5–5 mm
- Spikelets spiny
- the spikelets do not appear spiny
-
Leaves
- Leaf auricles
- the leaves do not have auricles
- Leaf blade width
- 3–4 mm
- Leaf ligule length
- Up to 1 mm
- Leaf ligule type
-
- the leaf ligule is in the form of a membrane with fine hairs
- the leaf ligule is in the form of fine hairs
- 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 hairs on the surface of the leaf sheath, and some of the hairs have blisters at their bases
- Leaf sheath hairs
- there are no hairs on the surface of the leaf sheath
-
Place
- Habitat
- terrestrial
- New England state
- Massachusetts
- Specific habitat
- man-made or disturbed habitats
Wetland status
Not classified
In New England
Distribution
- Connecticut
- absent
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- absent
Conservation status
None
From Flora Novae Angliae dichotomous key
2. Dactyloctenium radulans (R. Br.) Beauv. E
button grass. Eleusine radulans R. Br. • MA. Wool waste, disturbed soil.
Native to North America?
No
Sometimes confused with
- Dactyloctenium aegyptium:
- inflorescence not congested, with divergent branches 15–60 mm long; axis of each branch prolonged beyond the apical-most spikelet for 1–6 mm (vs. D. radulans, with the inflorescence subglobose, congested, with branches 4–15 mm long; axis of each branch prolonged beyond the apical-most spikelet for 1–1.5 mm).
Synonyms
- Eleusine radulans R. Br.