Callitriche hermaphroditica — autumn water-starwort
![Plant form: Callitriche hermaphroditica. ~ By William Alverson. ~ Copyright © 2024 William Alverson. ~ quararibea[at]gmail.com ~ Robert W. Freckmann Herbarium, U. of Wisconsin-Stevens Point](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Plantaginaceae/callitriche-hermaphroditica-ha-walverson.jpg)
![Flowers and fruits: Callitriche hermaphroditica. ~ By Gerry Carr. ~ Copyright © 2024 Gerry Carr. ~ gdcarr[at]comcast.net ~ Oregon Flora Image Project - www.botany.hawaii.edu/faculty/carr/ofp/ofp_index.htm](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Plantaginaceae/callitriche-hermaphroditica-ff-gcarr1-b.jpg)
![Flowers and fruits: Callitriche hermaphroditica. ~ By Gerry Carr. ~ Copyright © 2024 Gerry Carr. ~ gdcarr[at]comcast.net ~ Oregon Flora Image Project - www.botany.hawaii.edu/faculty/carr/ofp/ofp_index.htm](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Plantaginaceae/callitriche-hermaphroditica-ff-gcarr1-a.jpg)
![Leaves: Callitriche hermaphroditica. ~ By Gerry Carr. ~ Copyright © 2024 Gerry Carr. ~ gdcarr[at]comcast.net ~ Oregon Flora Image Project - www.botany.hawaii.edu/faculty/carr/ofp/ofp_index.htm](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Plantaginaceae/callitriche-hermaphroditica-le-gcarr1-b.jpg)
![Leaves: Callitriche hermaphroditica. ~ By Gerry Carr. ~ Copyright © 2024 Gerry Carr. ~ gdcarr[at]comcast.net ~ Oregon Flora Image Project - www.botany.hawaii.edu/faculty/carr/ofp/ofp_index.htm](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Plantaginaceae/callitriche-hermaphroditica-le-gcarr1-a.jpg)
![Inflorescences: Callitriche hermaphroditica. ~ By Gerry Carr. ~ Copyright © 2024 Gerry Carr. ~ gdcarr[at]comcast.net ~ U. of Washington - WTU - Herbarium - biology.burke.washington.edu/herbarium/imagecollection.php](https://newfs.s3.amazonaws.com:443/taxon-images-1000s1000/Plantaginaceae/callitriche-hermaphroditica-in-gcarr2.jpg)
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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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enlargeFacts
Autumn water-starwort, an annual aquatic of shallow lake water, has a circumboreal distribution, but is rare and protected in New England, being found only in Lake Champlain, Vermont. Water starworts (Callitriche) are remarkable for having flowers able to be pollinated by wind when emergent (anemophily), by water when floating at the surface (epihydrophily), as well as when submerged (hypohydrophily).
Habitat
Lacustrine (in lakes or ponds)
Characteristics
- Habitat
- aquatic
- New England state
-
- Connecticut
- Massachusetts
- Vermont
- Leaf position
- the leaves are all submerged underwater
- Leaf arrangement
- opposite: there are two leaves per node along the stem
- Leaf blade length
- 4–20 mm
- Petal or sepal number
- NA
- Petal color
- NA
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Floating leaf shape
- NA
- Underwater leaf blade width
- 0.6–2.2 mm
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Underwater leaf length
- 5.5–15.3 mm
-
Clonal plantlets
- Turion length
- 0 mm
-
Flowers
- Anther length
- 0.1–0.6 mm
- Carpels fused
- the carpels are fused to one another
- Flower lower lip length
- 0 mm
- Flower number
- 1
- Flower position
- the flowers are below the surface of the water
- Flower symmetry
- NA
- Inflorescence type
-
- the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
- the inflorescence has only one flower on it
- Nectar spur
- the flower has no nectar spurs
- Number of carpels
- 2
- Ovary position
- the sepals and/or petals are attached below the ovary
- Palate on corolla
- NA
- Petal and sepal arrangement
- the flower includes neither petals nor sepals
- Petal appearance
- NA
- Petal color
- NA
- Petal fringed edges
- NA
- Petal fusion
- NA
- Petal hairs on inner/upper surface
- NA
- Petal length
- 0 mm
- Petal number
- 0
- Petal or sepal number
- NA
- Pistil number
- 1
- Sepal appearance
- NA
- Sepal length
- 0 mm
- Sepal number
- 0
- Sepals fused only to sepals
- NA
- Spur length
- 0 mm
- Stamen length
- 0.6–1.5 mm
- Stamen number
- 1 or 2
- Stamen position relative to petals
- NA
- Stamens fused
- NA
- Stamens fused to petals
-
- NA
- the stamens are not fused to the petals or tepals
- Style length
- 0.6–2.5 mm
- Style number
- 2
-
Fruits or seeds
- Fruit length
- 1–2 mm
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Fruit type (specific)
- the fruit is a schizocarp (when dry it splits into sections, each holding one or more seeds)
- Fruit width
- 1.5–2.5 mm
-
Glands or sap
- Oil glands on nodes
- none of the nodes have oil glands
- Sap
- the sap is clear and watery
-
Growth form
- Lifespan
- the plant lives more than two years
- Root septa
- the roots do not have transverse septa
- Roots floating in water
- there are no clusters of roots floating in the water
- Turions
- there are no turions on the plant
- Underground organs
- there are only slender roots on the plant
-
Leaves
- Bract position (Sparganium)
- NA
- Bract relative length
- At least 3854 mm
- Bracts
- neither the flowers nor their pedicels have bracts
- Floating leaf basal lobes
- NA
- Floating leaf blade width
- 0 mm
- Floating leaf length
- 0 mm
- Floating leaf shape
- NA
- Floating leaf tip
- NA
- Floral bract form
- NA
- Floral bract length
- 0 mm
- Leaf arrangement
- opposite: there are two leaves per node along the stem
- Leaf blade length
- 4–20 mm
- Leaf blade veins
- the lateral veins radiate from the base and continue to spread away from the centerline of the leaf, or branch off the central vein at intervals
- Leaf blade width
- 0.6–2.2 mm
- Leaf position
- the leaves are all submerged underwater
- Leaf special features
- none of the mentioned special features are present
- Leaf-like branch segments
- 0
- Leaf-like branch shape
- NA
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Staminate bract edge (Myriophyllum)
- NA
- Stipule appearance
- NA
- Stipule fused to leaf
- NA
- Stipules
- there are no stipules on the plant
- Stipules fused around stem
- NA
- Trap-bladder length
- 0 mm
- Underwater leaf blade edges
- the underwater leaf has smooth edges, without teeth
- Underwater leaf blade shape
-
- the underwater leaf blade is linear (very narrow with more or less parallel sides)
- the underwater leaf blade is oblong (rectangular but with rounded ends)
- Underwater leaf blade veins
- 1
- Underwater leaf blade width
- 0.6–2.2 mm
- Underwater leaf length
- 5.5–15.3 mm
- Underwater leaf stalk
- no
- Underwater leaf tip shape
-
- the tip of the underwater leaf is retuse (blunt or rounded, with a notch at the tip)
- the tip of the underwater leaf is rounded, with no point
- Veins in floating leaf
- 0
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Massachusetts
- Vermont
- Specific habitat
- in lakes or ponds
-
Stem, shoot, branch
- Flowering stem growth form
- the flowering stem trails along the substrate, or floats in the water
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
New England distribution and conservation status
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Vermont
- historical (S-rank: SH)
Native to North America?
Yes
Sometimes confused with
- Callitriche stagnalis:
- leaves dimorphic, the floating ones with 5-7 veins by branching of the lateral veins, and flowers and fruits subtended by 2 white or translucent bracts (vs. C. hermaphroditica, with leaves monomorphic, all with 1 vein, and flowers and fruits without subtending bracts).
- Callitriche terrestris:
- fruit 0.5-0.7 mm long, borne on a short pedicel 0.1-0.6 mm long, each half of the fruit with an inconspicuous wing-margin, and leaf blades 2-5 mm long (vs. C. hermaphroditica, with fruit 1-2 mm long, subsessile, each half of the fruit with an conspicuous wing-margin, and leaf blades mostly 4-15 mm long).
Synonyms
- Callitriche autumnalis L.
Family
Genus
From the dichotomous key of Flora Novae Angliae
1. Callitriche hermaphroditica L. NC
autumn water-starwort. Callitriche autumnalis L. • CT, MA, VT, most collections within Lake Champlain. Shallow water of lakes and rivers. Callitriche hermaphroditica is unique among New England members of this genus in having distinct leaves and lacking leaf scales (the remaining species have leaves at each node with connate bases and leaf blades that appear minutely punctate due to the presence of leaf scales).