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- Oligoneuron
- Oligoneuron rigidum
Oligoneuron rigidum — stiff flat-topped-goldenrod
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Facts
Stiff flat-topped-goldenrod reaches the edge of its natural range in New England, where it is very rare, occurring historically in Massachusetts and Rhode Island, and currently found in only a few populations in Connecticut, on limestone ledges and on dry, sandy and rocky soils near the coast. Its flowering heads are large and few, compared to those of other goldenrod species. The main threats to New England populations include shading and competition from other plant species, and browsing by white-tailed deer.
Habitat
Forest edges
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
- Massachusetts
- Rhode Island
- Leaf type
- leaves are simple (lobed or unlobed but not separated into leaflets)
- Leaf arrangement
-
- alternate: there is one leaf per node along the stem
- the leaves are growing only at the base of the plant (basal)
- Leaf blade edges
- the edge of the leaf blade has teeth
- Flower type in flower heads
- the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
- Ray flower color
- yellow
- Tuft or plume on fruit
- at least a part of the plume is made up of fine bristles
- Spines on plant
- the plant has no spines
- Leaf blade length
- 60–300 mm
- Flower head width
- anything
- Disk flower number
-
- 11-20
- 21-50
-
Flowers
- Bract cycle number
- there are three or more cycles of bracts
- Bract outer side hair type
-
- the bracts are hairy, with simple hairs on their outer surface
- the bracts are not hairy on their outer surface
- Bract outer side hairs
-
- the bracts are hairy on their outer surfaces
- the bracts are not hairy on their outer surfaces
- Bract shape
- the main bracts are oblong (roughly rectangular but rounded at the ends)
- Bract spines
- the bracts have no spines
- Bract tip extension appearance
- NA
- Bract tip extension edge
- there are no projections from the bract tips
- Bract tip orientation
- the bracts are pressed against the plant, or spreading out at the tips
- Bract tip shape
- the tips of the bracts are rounded
- Bracts
- there are at least two distinct forms of bracts in different cycles
- Disk flower color
- white
- 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
- Disk flower shape
- the disk flower is abruptly widened at some point below the lobes
- Disk width
- 5–10 mm
- Flower head number
- each flowering stem has four or more flower heads on it
- Flower head outer flowers
- at the outer edge of the flower head, each flower has a single enlarged lobe or strap
- Flower head platform
- the base has no bristles or papery scales
- Flower head platform surface
- NA
- Flower head position
- some or all the flower heads are grouped in clusters of two or more
- Flower head profile
- the disk is rounded across the top
- Flower head shape
- the sides of the flower head are roughly parallel, like a cylinder
- Flower head width
- anything
- Flower type in flower heads
- the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
- Height of flower head base
- 6–8 mm
- Inflorescence branching (Solidago)
- NA
- Inflorescence shape
- the inflorescence is flat-topped in profile
- Inflorescence stem
-
- hairs are present on the stem of the inflorescence
- the stem of the inflorescence is not hairy
- Number of bracts at flower head base
- 10–35
- Ovary beak
- there is no beak on the ovary
- Ovary cross-section
-
- the ovary has five or more corners in cross-section
- the ovary is compressed (flattened)
- 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 ten or more ribs visible on the ovary
- Ovary profile
- in profile, the ovary is another shape
- Peduncle hair type
- the hairs on the peduncles are simple (not branched), don’t have glands, and are not woolly
- Peduncle hairs
- the peduncles are hairy
- Peduncle length
- 3–15 mm
- Peduncle orientation
- the flower heads are held upright, or slightly angled outwards
- Ray flower color
- yellow
- Ray flower reproductive parts
- the ray flowers have carpels or stamens, but not both
- Ray flowers
-
- 11-15
- 6-10
- Ray length
- 3–5 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
- Smaller bracts at base of bracts
- there is a cycle of much smaller bracts outside the cycle of larger and longer bracts
- Style branch number
- the style has two branches
- Width of flower head base
- 5–7 mm
-
Fruits or seeds
- Number of pappus parts
- 11 or more
- Ovary length in developed fruit
- 0.7–1.7 mm
- Seed hair tuft details
- the pappus hairs are hooked or barbed
- Seed hair tuft length
- 3–4 mm
- Seed hair tuft tips
- the pappus hairs are slender
- Seed hairs uniform
- there are two distinct lengths of pappus hairs
- Seed tuft scale number
- 0
- Seed tuft type
- the pappus is made of very fine hairs or bristles
- Top of disk flower ovary
- NA
- Tuft or plume on fruit
- at least a part of the plume is made up of fine bristles
-
Glands or sap
- Leaf blade glands
- the leaf blades have glandular (translucent) dots or scales
- 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 perennial, it shows evidence of previous year's leaves, stems or stem bases
- Spines on plant
- the plant has no spines
- Underground organs
-
- the plant has a caudex (the root mass is firm and hardened at the top)
- the plant has a rhizome (a horizontal underground stem with roots growing from it)
-
Leaves
- Final leaf segment length (compound lvs only)
- 0 mm
- Final leaf segment width (compound lvs only)
- 0 mm
- Hairs on underside of leaf blade
- the underside of the leaf is fuzzy or hairy
- Hairs on upper side of leaf blade
- the upper side of the leaf is fuzzy or hairy
- Leaf arrangement
-
- alternate: there is one leaf per node along the stem
- the leaves are growing only at the base of the plant (basal)
- Leaf blade base
-
- the leaf has a distinct petiole
- the leaf has no petiole
- the leaf has no petiole and at the base it clasps the stem, or goes all the way around the stem so the stem appears to pierce the leaf
- 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
- Leaf blade bloom
- the underside of the leaf has no noticeable bloom
- Leaf blade edges
- the edge of the leaf blade has teeth
- Leaf blade flatness
- the leaf is flat (planar) at the edges
- Leaf blade hairs
- the leaf blade has simple hairs with no glands, and not tangled or wooly
- Leaf blade length
- 60–300 mm
- Leaf blade shape
-
- the leaf blade is elliptic (widest near the middle and tapering at both ends)
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is oblong (rectangular but with rounded 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 tip
-
- the tip of the leaf blade is acute (sharply pointed)
- the tip of the leaf blade is obtuse (bluntly pointed)
- Leaf blade veins
- the leaf blade has one main vein running from the base towards the tip
- Leaf blade width
- 15–100 mm
- Leaf disposition
- the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
- Leaf spines
- there are no spines on the leaf edges
- Leaf stalk
-
- the leaves have leaf stalks
- the leaves have no leaf stalks, but attach directly to the stem
- Leaf tufts in axils
- there are no clusters of smaller leaves
- Leaf type
- leaves are simple (lobed or unlobed but not separated into leaflets)
- Leaflet number
- 0
- Specific leaf type
- the leaves are simple (lobed or unlobed but not separated into leaflets
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Massachusetts
- Rhode Island
- Specific habitat
- edges of forests
-
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 internode hair direction
- the hairs point mostly upwards to outwards
- Stem internode hair type
- the hairs on the stem are plain, without glands or branches, and not tangled
- Stem internode hairs
- the stem has hairs between the nodes
Wetland status
Not classified
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.
- Connecticut
- extremely rare (S-rank: S1), endangered (code: E)
var. rigidum
- Rhode Island
- historical (S-rank: SH), state historical (code: SH)
From Flora Novae Angliae dichotomous key
2. Oligoneuron rigidum (L.) Small var. rigidum NC
stiff flat-topped-goldenrod. Solidago rigida L. • CT, MA, RI. Forest borders, banks and plains near the coast, woodlands on high-pH bedrock.