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- Poaceae Group 10
- Dichanthelium
- Dichanthelium commutatum
Dichanthelium commutatum — variable rosette-panicgrass
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Facts
Ashe's variable rosette-panicgrass is native to southern and eastern North America, including New England, where it reaches the northeastern limit of its range. It grows in woodlands and sandy fields.
Habitat
Meadows and fields, woodlands
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
- Rhode Island
- Leaf blade width
- 5–10 mm
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Spikelet length
- 2.2–3.2 mm
- Glume relative length
-
- neither glume is quite as long as all of the florets
- 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 sheath hair type
-
- there are hairs on the surface of the leaf sheath, but the hairs do not have blisters at their bases
- there are no hairs on the surface of the leaf sheath
- Leaf ligule length
- Up to 0.5 mm
-
Flowers
- Anther number
- 0–3
- 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
-
- neither glume is quite as long as all of the florets
- one or both glumes are as long or longer than 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 orientation
- the inflorescence axis is straight
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Inflorescence length
- 50–120 mm
- Inflorescence type (general)
- 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
- 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
- 7 or more
- 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
- 2.2–3.2 mm
- Spikelets spiny
- the spikelets do not appear spiny
- Upper glume shape
- the upper glume is widest at or below the middle
-
Growth form
- Lifespan
- the plant lives more than two years
- Roots
- the plant has a root mass with a hardened top
-
Leaves
- Basal leaves
- the plant has large or prominent tufts of leaves at the base of the flowering stem
- Leaf auricles
- the leaves do not have auricles
- Leaf blade base
- the leaf blade cuts in abruptly to the narrower base, or has rounded lobes on either side of the base (heart-shaped)
- Leaf blade width
- 5–10 mm
- Leaf ligule length
- Up to 0.5 mm
- Leaf ligule type
- the leaf ligule is in the form of a membrane with 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, but the hairs do not have blisters at their bases
- there are no hairs on the surface of the leaf sheath
- 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
- Rhode Island
- Specific habitat
-
- meadows or fields
- woodlands
-
Stem, shoot, branch
- Hairs at nodes
-
- the stem nodes are hairless or they have very sparse hairs
- the stem nodes have hairs that stand out at a shallow angle, or they curve downwards
- Stem hairs
- the stem has hairs on it
- 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.
ssp. ashei
- Massachusetts
- fairly widespread (S-rank: S4)
Subspecies and varieties
Our subspecies is Dichanthelium commutatum (J.A. Schultes) Gould ssp. ashei.
From Flora Novae Angliae dichotomous key
5. Dichanthelium commutatum (J.A. Schultes) Gould ssp. ashei (G. Pearson ex Ashe) Freckmann & Lelong N
variable rosette-panicgrass. Panicum ashei Pearson ex Ashe; P. commutatum (J.A. Schultes) Gould var. ashei (Pearson ex Ashe) Fern.; P. umbrosum Le Conte ex Torr. • CT, MA, RI; also reported from NH by Freckmann and Lelong (2003a), but specimens are unknown. Woodlands, openings, sandy fields. Dichanthelium commutatum was reported from ME by Gould and Clark (1978), but the seasonal development of the specimen is in contradiction with the collection date. The specimen is believed to be from much farther south and the result of a label mix-up (Robert Freckmann, personal communication). Reports of Dichanthelium commutatum ssp. commutatum from New England appear to be in error. Those specimens identified as such and seen by Robert Freckmann or me were misidentified.
Native to North America?
Yes
Sometimes confused with
- Dichanthelium latifolium:
- stems glabrous or shortly pilose, ligules 0.4-0.9 mm long, and spikelets 2.9-5.2 mm long (vs. D. commutatum, with stems densely crisp-puberulent, ligules up to 0.3 mm long, and spikelets 2.2-3.2 mm long).
Synonyms
- Panicum ashei Pearson ex Ashe
- Panicum commutatum (J.A. Schultes) Gould var. ashei (Pearson ex Ashe) Fern.
- Panicum umbrosum Le Conte ex Torr.