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- Artemisia biennis
Artemisia biennis — biennial wormwood
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Facts
Biennial wormwood is considered native to the northwestern United States, but is introduced and weedy in the majority of its current range, including in New England. It is considered a noxious weed of crops in the northern Great Plains, especially since the rise of no-till agricultural practices between 1990 and 2000.
Habitat
Anthropogenic (man-made or disturbed habitats), 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.
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Characteristics
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf type
- leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade edges
-
- the edge of the leaf blade has lobes, or it has both teeth and lobes
- the edge of the leaf blade has teeth
- Flower type in flower heads
- the flower head has disk flowers only, and lacks the strap-shaped flowers
- Ray flower color
- NA
- Tuft or plume on fruit
- NA
- Spines on plant
- the plant has no spines
- Leaf blade length
- 40–130 mm
- Flower head width
- 1.5–4 mm
- Disk flower number
-
- 11-20
- 21-50
-
Flowers
- Bases of bract appendages
- NA
- Bract cycle number
- there are three or more cycles of bracts
- Bract inner side hairs
- the bracts are not hairy on their inner surfaces
- Bract outer side hair type
- the bracts are not hairy on their outer surface
- Bract outer side hairs
- the bracts are not hairy on their outer surfaces
- Bract separation
- the bracts appear completely unconnected to one another on all flower heads
- Bract shape
-
- the main bracts are elliptic (widest near the middle and tapered towards the base and tip)
- the main bracts are obovate (roughly egg-shaped, but widest near the tip)
- Disk flower color
- yellow
- Disk flower lobe number
- 5
- Disk flower number
-
- 11-20
- 21-50
- Disk flower reproductive parts
-
- the disk flower has both pollen- and seed-producing parts
- the disk flower has either only pollen- or only seed-producing parts
- Flower head outer flowers
- at the outer edge of the flower head, the flowers have no enlarged lobe or strap, and are of similar size as those in the center of the disk
- Flower head platform
- the base has no bristles or papery scales
- Flower head platform surface
- NA
- Flower head width
- 1.5–4 mm
- Flower type in flower heads
- the flower head has disk flowers only, and lacks the strap-shaped flowers
- Height of flower head base
- 2–3 mm
- Inflorescence branching (Solidago)
- NA
- Inflorescence shape
- the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
- Ovary cross-section
- the ovary has five or more corners in cross-section
- Ovary hair type
- the ovary has no hairs on it
- Ovary hairs
- the ovary has no hairs on it
- Ovary lines or ribs
- there are four to six lines or ribs visible on the ovary
- Ovary profile
- in profile, the ovary is roughly elliptical (widest in the middle, tapering to both ends)
- Ray flower color
- NA
- Ray flower reproductive parts
- NA
- Ray flowers
- 0
- Ray length
- 0 mm
- Reproductive system
- some of the flowers on the plant have only carpels or stamens, while others have both carpels and stamens
- Scale tip
- NA
- Width of flower head base
- 1.5–4 mm
-
Fruits or seeds
- Number of pappus parts
- 0
- Ovary length in developed fruit
- 0.2–0.9 mm
- Seed hair tuft bases
- NA
- Seed hair tuft color
- NA
- Seed hair tuft details
- NA
- Seed hair tuft length
- 0 mm
- Seed hair tuft tips
- NA
- Seed hairs uniform
- NA
- Seed tuft scale number
- 0
- Seed tuft type
- there is no pappus on the ovary
- Top of disk flower ovary
- NA
- Tuft or plume on fruit
- NA
-
Glands or sap
- Sap
- the sap is clear and watery
-
Growth form
- Growth form
- the plant has one or more free-standing stems
- Plant lifespan
-
- the plant is annual, it lacks evidence of previous years' growth
- the plant is biennial, it appears as either first year (non-reproductive) plants or second year plants with flowers or fruit
- Spines on plant
- the plant has no spines
- Underground organs
- there is a thickened taproot on the plant
-
Leaves
- Hairs on underside of leaf blade
- the underside of the leaf is not hairy, or has very few hairs
- Hairs on upper side of leaf blade
- the upper side of the leaf is not hairy, or has very few hairs
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade base
-
- the leaf has a distinct petiole
- the leaf has no petiole
- Leaf blade base shape
-
- the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
- the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)
- Leaf blade bloom
- the underside of the leaf has no noticeable bloom
- Leaf blade edges
-
- the edge of the leaf blade has lobes, or it has both teeth and lobes
- the edge of the leaf blade has teeth
- Leaf blade hairs
- NA
- Leaf blade length
- 40–130 mm
- Leaf blade shape
-
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- Leaf blade surface colors
- there is no noticeable color variation on the upper surface of the leaf
- Leaf blade width
- 15–40 mm
- Leaf disposition
- the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
- Leaf spines
- there are no spines on the leaf edges
- Leaf stalk
- the leaves have no leaf stalks, but attach directly to the stem
- Leaf tip extension
- NA
- Leaf type
- leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
- Leaflet number
- 0
- Specific leaf type
-
- the leaf has a row of two or more lobes on each side of the central axis
- the leaf has a row of two or more lobes on each side of the central axis, and each lobe itself has rows of lobes on each side of the lobe's central axis
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- man-made or disturbed habitats
- meadows or fields
-
Scent
- Plant odor
- the plant does not have much of an odor
-
Stem, shoot, branch
- Flowering stem cross-section
- the flowering stem is circular, or with lots of small angles
- Leaves on stem
- there is at least one full leaf above the base of the flowering stem
- Stem bloom
- there is no powdery or waxy film on the stem
- Stem internode hair direction
- NA
- Stem internode hair length
- 0 mm
- Stem internode hair type
- the stem has no hairs between the nodes
- Stem internode hairs
- the stem has no hairs between the nodes
- Stem wings
- the stem does not have wings on it
Wetland status
Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)
In New England
Distribution
- Connecticut
- present
- Maine
- present
- 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.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
4. Artemisia biennis Willd. E
biennial wormwood. CT, MA, ME, NH, RI, VT. Roadsides, railroads, fields, disturbed soil.
Native to North America?
Yes
Sometimes confused with
- Artemisia annua:
- lower heads nodding and borne on evident stalks and foliage aromatic (vs. A. biennis, with flower heads upright on inconspicuous stalks and foliage with little or no scent).