Triosteum angustifolium — lesser horse-gentian
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Facts
Lesser horse-gentian is native to southern and eastern North America. It is rare in New England at the northeastern limit of its range, and can be found only in western Connecticut in rocky forests and woodlands, ledges and railroads.
Habitat
Forests, ridges or ledges, talus and rocky slopes, 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.
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enlargeCharacteristics
- Habitat
- terrestrial
- New England state
- Connecticut
- Flower petal color
-
- green to brown
- yellow
- Leaf type
- the leaves are simple (lobed or unlobed but not separated into leaflets)
- Leaf arrangement
- opposite: there are two leaves per node along the stem
- Leaf blade edges
- the edge of the leaf blade is entire (has no teeth or lobes)
- Flower symmetry
- there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
- Number of sepals, petals or tepals
- there are five petals, sepals, or tepals in the flower
- Fusion of sepals and petals
- the petals or the sepals are fused into a cup or tube
- Stamen number
- 5
- Fruit type (general)
- the fruit is fleshy
-
Clonal plantlets
- Bulbils
- the plant does not appear to have bulbils
- Bulblets replace flowers
- there are no bulblets where the flowers are located
-
Flowers
- Anther opening
- the anthers have narrow slits or furrows that run lengthwise along the anthers
- Anther spurs
- the anthers do not have spurs on them
- Calyx symmetry
- there are two or more ways to evenly divide the calyx (the calyx is radially symmetrical)
- Carpels fused
- the carpels are fused to one another
- Cleistogamous flowers
- there are no cleistogamous flowers on the plan
- Corolla palate
- no
- Corona lobe length
- 0 mm
- Epicalyx
- the flower does not have an epicalyx
- Epicalyx number of parts
- 0
- Flower description
- the flower has an inferior ovary, with or without a hypanthium
- Flower petal color
-
- green to brown
- yellow
- Flower reproductive parts
- the flower has both pollen- and seed-producing parts
- Flower symmetry
- there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
- Flowers sunken into stem
- no
- Form of style
-
- the style is knob-like at the tip, and unbranched
- the style is lobed at the tip, and unbranched
- Fusion of sepals and petals
- the petals or the sepals are fused into a cup or tube
- Horns in hoods (Asclepias)
- NA
- Hypanthium
- the flower does not have a hypanthium
- Inflorescence one-sided
- the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks
- Inner tepals (Rumex)
- NA
- Nectar spur
- the flower has no nectar spurs
- Number of pistils
- 1
- Number of sepals, petals or tepals
- there are five petals, sepals, or tepals in the flower
- Ovary position
- the ovary is below the point of petal and/or sepal attachment
- Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
- Petal and sepal colors
-
- green to brown
- yellow
- Petal appearance
- the petals are thin and delicate, and pigmented (colored other than green or brown)
- Petal folds or pleats
- the petals of the flower do not have folds or plaits
- Petal hairs (Viola)
- NA
- Petal number
- 5
- Petal tips (Cuscuta)
- NA
- Scales inside corolla
- no
- Sepal and petal color
- the sepals are different from the petals
- Sepal appendages
- the sepals do not have appendages on them
- Sepal appendages (Oenothera)
- NA
- Sepal number
- 5
- Stamen attachment
- the stamens are attached at or near the bases of the petals or tepals
- Stamen number
- 5
- Stamen position relative to petals
- the stamens are lined up with the sepals
- Staminodes
- there are no staminodes on the flower
- Umbel flower reproductive parts
- NA
- Upper lip of bilabiate corolla
-
- NA
- the upper lip of the bilabiate corolla has two lobes
-
Fruits or seeds
- Achene relative orientation
- NA
- Achene shape
- NA
- Achene surface (Polygonum)
- NA
- Achene type
- NA
- Berry color
-
- orange
- red
- Capsule color (Viola)
- NA
- Capsule ribs
- NA
- Capsule splitting
- NA
- Fruit (pyxis) dehiscence
- NA
- Fruit beak length
- 0 mm
- Fruit features (Brassicaceae)
- NA
- Fruit locules
- four
- Fruit type (general)
- the fruit is fleshy
- Fruit type (specific)
- the fruit is a drupe (fleshy, with a firm inner ovary wall that encloses a single seed)
- Legumes (Fabaceae)
- NA
- Mericarp length
- 0 mm
- Mericarp segment shape (Desmodium)
- NA
- Other markings on berry
- the ripe berries are mostly one color without spots or streaks
- Ovary stipe
- the ovary or fruit does not have a stipe
- Placenta arrangement
- the plant has axile placentation, in which the ovules are attached where the septa of a compound ovary are united, usually on the central axis, or to the septa themselves
- Rows of seeds in fruit (Brassicaceae)
- NA
- Schizocarpic fruit compression
- NA
- Schizocarpic fruit segments
- 0
- Septum in fruit (Brassicaceae)
- NA
- Wings on fruit
- the fruit does not have wings on it
- prickles on fruits
- the fruits do not have thorn-like defensive structures
-
Glands or sap
- Glands on leaf blade
- the leaf blades do not have glandular dots or scales
- Sap
- the sap is clear and watery
- Sap color
- the sap is clear
-
Growth form
- Horizontal rooting stem
- the plant does not have stolons
- Lifespan
- the plant lives more than two years
- Parasitism
- the plant is not parasitic
- Plant color
- the leaves or young stems of the plant are green
- Spines on plant
- the plant has no spines
-
Leaves
- Bracteole number (Apiaceae)
- 0
- Bracts in plantain (Plantago)
- NA
- Final leaf segment length (compound lvs only)
- 0 mm
- Final leaf segment length to width ratio (compound lvs only)
- 0
- Final leaf segment width (compound lvs only)
- 0 mm
- Hairs on underside of leaf
-
- the underside of the leaf is fuzzy or hairy
- the underside of the leaf is not hairy, or it has very few hairs
- Leaf arrangement
- opposite: there are two leaves per node along the stem
- Leaf blade base
- the leaf has no stalk
- 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 edges
- the edge of the leaf blade is entire (has no teeth or lobes)
- Leaf blade length
- 80–180 mm
- Leaf blade shape
-
- the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
- the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
- Leaf blade surface colors
- the upper side of the leaf blade is relatively uniform in color
- Leaf duration
- the leaves drop off in winter (or they whither but persist on the plant)
- Leaf form
- the leaves are green, with an expanded blade and a leaf-like texture
- Leaf spines
- there are no spines on the leaf edges
- Leaf type
- the leaves are simple (lobed or unlobed but not separated into leaflets)
- Leaflet petiolules
- NA
- Leaves per node
- there are two leaves per node along the stem
- Specific leaf type
- the leaves are simple (lobed or unlobed but not separated into leaflets)
- Stipels
- NA
- Stipule features
- NA
- Stipules
- there are no stipules on the plant
-
Place
- Habitat
- terrestrial
- New England state
- Connecticut
- Specific habitat
-
- forests
- ridges or ledges
- talus or rocky slopes
- woodlands
-
Scent
- Plant odor
- the plant does not have much of a smell
-
Stem, shoot, branch
- Branched tendrils
- NA
- Hairs between stem nodes
- at least some of the hairs on the stem have glands
- Hooked hairs on stem between nodes
- no
- Leaves on stem
- there is at least one full leaf above the base of the flowering stem
- Plant height
- 30–80 cm
- Tendril origin
- NA
- Tendrils
- the plant does not have tendrils
Wetland status
Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)
In New England
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- absent
- 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.
- Connecticut
- extremely rare (S-rank: S1), endangered (code: E)
var. eamesii
- Connecticut
- historical (S-rank: SH)
From Flora Novae Angliae dichotomous key
1. Triosteum angustifolium L. NC
lesser horse-gentian. CT; western portion of state. Rocky forests and woodlands, ledges, railroads.
1×2. Triosteum angustifolium × Triosteum aurantiacum → Triosteum ×eamesii (Wieg.) A. Haines is a rare horse-gentian hybrid that is known from CT and was formerly treated as Triosteum angustifolium var. eamesii Wieg. It most resembles T. angustifolium due to its short sepals and long-pubescent stems. It has leaf blades mostly 2.2–3.2 times a long as wide that are moderately puberulent abaxially and dried stems (3–) 4–7 mm thick at the midpoint (vs. leaf blades mostly 3.5–7 times as long as wide that are sparsely pubescent abaxially and dried stems 2–2.7 mm thick at the midpoint in T. angustifolium). Recognition of this hybrid shows T. angustifolium to be far more rare than previously believed because many collections of T. angustifolium were of the var. eamesii (i.e., they were hybrid plants).
Native to North America?
Yes