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- Spiranthes tuberosa
Spiranthes tuberosa — little ladies'-tresses
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Facts
Little ladies'-tresses is primarily a species of the southern and southeastern states, but it enters New England (Connecticut, Massachusetts and Rhode Island) at the northern limit of its distribution. It is relatively common in much of its range, but not so in New England. It is distinguished from close relatives by its pure white flowers and single tuberous root (occasionally the previous year's tuber persists).
Habitat
Anthropogenic (man-made or disturbed habitats), grassland, 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.
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Characteristics
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Massachusetts
- Rhode Island
- Leaf arrangement
- basal: the leaves are growing only at the base of the plant
- Number of leaves on stem
- absent
- Form of lower petal
- the labellum does not have a pouch-like shape
- Lower petal outline
- the labellum is simple in form
- Main color of lower petal
- white
- Nectar spur
- there are no nectar spurs on the flower
- Inflorescence type
- the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
- Lower petal characteristics
- the labellum is simple in form
- Sepal length
- 3–5 mm
-
Flowers
- Flower petal color
- white
- Flower symmetry
- there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
- Flowering date
-
- August
- September
- Flowers per inflorescence
- 8–30
- Form of lower petal
- the labellum does not have a pouch-like shape
- Hairs on flower stalk
- NA
- Hairs on inflorescence axis
- the main stem of the inflorescence is hairless
- Inflorescence length
- 15–80 mm
- Inflorescence type
- the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
- Labellum position
- the labellum is in the lower position on the flower
- Length of flower stalk
- 0 mm
- Lobes at base of lower petal
- 0 mm
- Lower petal characteristics
- the labellum is simple in form
- Lower petal outline
- the labellum is simple in form
- Lower petal strongly red-veined
- no
- Main color of lower petal
- white
- Nectar spur
- there are no nectar spurs on the flower
- Nectar spur length
- 0 mm
- Number of stamens
- 1
- Orientation of side petals
-
- the lateral petals are angled steeply upwards
- the lateral petals slant somewhat downward
- Self-pollinating flowers
- there are no cleistogamous flowers on this plant
- Sepal length
- 3–5 mm
- Sepals fused only to sepals
- the sepals are separate from one another
- Shape of viscidium
-
- the viscidium is lance-shaped (wider near one end, pointed at the ends)
- the viscidium is long and narrow
- Spots on lower petal
- no
- Spur opening membrane
- NA
- Spur opening shape
- NA
-
Fruits or seeds
- Seed capsule orientation
- the capsule points upwards or is angled outwards
-
Growth form
- Plant green or not
- the plant is chlorophyllous (it has green parts)
- Roots
- the rhizomes do not resemble coral
- Underground organs
-
- the plant has one or more swollen storage organs underground, such as bulbs, tubers or corms
- there are only slender roots on the plant
-
Leaves
- Bract relative length
- the bract is shorter than the associated flower
- Features of leaves
- the leaf does not have any of the mentioned special features
- Leaf arrangement
- basal: the leaves are growing only at the base of the plant
- Leaf blade edges
- the edges of the leaf blade have no teeth
- Leaf blade length
- 20–60 mm
- Leaf blade length to width ratio
- 2–3
- 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 ovate (widest below the middle and broadly tapering at both ends)
- 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 width
- 10–20 mm
- Leaves during flowering
-
- there are leaves on the plant when it is flowering
- there are no leaves on the plant when it is flowering
- Number of bracts on stem
- 4–6
- Number of leaves on stem
- absent
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Massachusetts
- Rhode Island
- Specific habitat
-
- grasslands
- man-made or disturbed habitats
- meadows or fields
- woodlands
Wetland status
Occurs only in non-wetlands. (Wetland indicator code: UPL)
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
- unranked (S-rank: SNR)
- Massachusetts
- uncommon to fairly widespread (S-rank: S3S4)
- Rhode Island
- extremely rare (S-rank: S1), state endangered (code: SE)
var. grayi
- Connecticut
- unrankable (S-rank: SU), special concern (code: SC)
From Flora Novae Angliae dichotomous key
7. Spiranthes tuberosa Raf. N
little ladies’-tresses. Gyrostachys beckii (Lindl.) W. Stone, sensu Eames; Spiranthes tuberosa Raf. var. grayi (Ames) Fern. • CT, MA, RI. Fields, roadsides, open woodlands, lawns.
Native to North America?
Yes
Sometimes confused with
- Spiranthes lacera:
- labellum white with a central green or yellow-green spot, rachis of inflorescence sparsely pubescent or glabrous, and roots few to several, up to 7.5 mm wide (vs. S. tuberosa, with labellum white, rachis of inflorescence glabrous, and root solitary or rarely divided at the tip, 4–12 mm wide).
- Spiranthes vernalis:
- rachis of inflorescence mostly or entirely pubescent with non-glandular hairs, glands of rachis, if present, narrower or equal to width of stipe, therefore, the hairs pointed or cylindrical, and labellum usually cream-yellow centrally (vs. S. tuberosa, with rachis of inflorescence pubescent, in part, with glandular hairs, glands of rachis wider than stipe, therefore, the hairs capitate at their apex, and labellum pure white).
Synonyms
- Gyrostachys beckii (Lindl.) W. Stone, sensu Eames
- Spiranthes tuberosa Raf. var. grayi (Ames) Fern.