Tragus berteronianus — spike burgrass
![Spikelets: Tragus berteronianus. ~ By Elizabeth Farnsworth. ~ Copyright © 2025 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Poaceae/tragus-berteronianus-si-efarnsworth.jpg)
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Facts
Spike burgrass is an annual, mat-forming grass that is a significant invader of disturbed areas in some parts of the world, but in New England is only an occasional visitor via waste areas of ninteenth-century wool-carding factories, and ships' ballast dumps.
Habitat
Anthropogenic (human-disturbed or -maintained 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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enlargeCharacteristics
- Habitat
- terrestrial
- New England state
-
- Maine
- Massachusetts
- Leaf blade width
- 1.2–5 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
- 0.8–4.3 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 one floret per spikelet
- Lemma awn length
- 0 mm
- Leaf ligule length
- 0.5–1 mm
- Anther length
- 0.4–0.6 mm
-
Flowers
- Anther length
- 0.4–0.6 mm
- Anther number
- 3
- Awn on glume
- the glume has no awn
- Floret lower bract texture
- the lemma is thin and flexible
- Glume relative length
- one or both glumes are as long or longer than all of the florets
- Glume veins
-
- 0
- 5
- 7 or more
- Inflorescence axis orientation
-
- the inflorescence axis is arched or curved outward
- the inflorescence axis is straight
- Inflorescence branch length
- 0.05–0.27 cm
- 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 length
- 10–130 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
- 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 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
- One or more florets
- 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
- 0.8–4.3 mm
- Spikelet pedicel
- the spikelets have pedicels
- Spikelets spiny
- the spikelets appear spiny and bur-like
-
Leaves
- Leaf auricles
- the leaves do not have auricles
- Leaf blade width
- 1.2–5 mm
- Leaf ligule length
- 0.5–1 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)
-
Place
- Habitat
- terrestrial
- New England state
-
- Maine
- Massachusetts
- Specific habitat
- human-disturbed or -maintained habitats
-
Stem, shoot, branch
- Stem spacing
- the stems grow close together in compact clusters or tufts
Wetland status
Not classified
In New England
Distribution
- Connecticut
- absent
- Maine
- present
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
1. Tragus berteronianus J.A. Schultes E
spike burgrass. Nazia aliena, auct. non (Spreng.) Scribn. • MA, ME. Wool waste, ballast.
Native to North America?
No
Sometimes confused with
- Tragus racemosus:
- upper glume 7-veined, 3.8–6.6 mm long, with mostly 6 or 7 longitudinal rows of spine-like projections, and panicle branches 2.1–4.8 mm long (vs. T. berteronianus, with upper glume 5-veined, 1.8–4.3 mm long, with 5 longitudinal rows of spine-like projections, and panicle branches mostly 0.7–2.7 mm long).
Synonyms
- Nazia aliena, auct. non (Spreng.) Scribn.