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• Ceratophyllaceae
• Ceratophyllum
• Ceratophyllum echinatum

Ceratophyllum echinatum — spineless hornwort

Facts

Spineless hornwort is found only in North America, with populations in the Pacific Northwest disjunct from its main range in the East. It inhabits lakes and slow-moving streams throughout New England, but is less frequent than its sister species common hornwort (Ceratophyllum demersum). Spineless hornwort typically grows in clearer, more acidic waters than common hornwort.

Habitat

Lacustrine (in lakes or ponds), riverine (in rivers or streams)

Characteristics

• Clonal plantlets

  Turion length

  0 mm

• Flowers

  Anther length

  1–1.1 mm

  Carpels fused

  NA

  Flower lower lip length

  0 mm

  Flower number

  1

  Flower position

  the flowers are below the surface of the water

  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

  Length of flower stalk

  0–1 mm

  Nectar spur

  the flower has no nectar spurs

  Number of carpels

  1

  Ovary position

  the sepals and/or petals are attached below the ovary

  Palate on corolla

  NA

  Petal and sepal arrangement

  the flower includes only one cycle of petals or 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

  there are seven or more petals, sepals, or tepals in the flower

  Pistil number

  1

  Sepal appearance

  the sepals resemble leaves in color and texture

  Sepal length

  1.5–2 mm

  Sepal number

  7–15

  Sepals fused only to sepals

  • the sepals are fused to each other (not other flower parts), at least near their bases
  • the sepals are separate from one another

  Spur length

  0 mm

  Stamen number

  13 or more

  Stamen position relative to petals

  NA

  Stamens fused

  the stamens are not fused to one another

  Stamens fused to petals

  the stamens are not fused to the petals or tepals

  Style length

  5–10 mm

  Style number

  1

• Fruits or seeds

  Fruit length

  4.5–6 mm

  Fruit type (general)

  the fruit is dry but does not split open when ripe

  Fruit type (specific)

  the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)

  Fruit width

  2.5–4.5 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

  NA

  Roots floating in water

  NA

  Turions

  there are no turions on the plant

  Underground organs

  NA

• Leaves

  Bract position (Sparganium)

  NA

  Floating leaf basal lobes

  no

  Floating leaf blade width

  Up to 0.5 mm

  Floating leaf length

  0 mm

  Floating leaf shape

  • the leaf blade is linear (very narrow with more or less parallel sides)
  • the leaf is capillary (very fine and hair-like)

  Floating leaf tip

  the tip of the floating leaf blade is acuminate (tapers to a long, thin point)

  Leaf arrangement

  whorled: there are three or more leaves per node along the stem

  Leaf blade length

  15–20 mm

  Leaf blade width

  Up to 0.5 mm

  Leaf position

  • some of the leaves are floating at the surface of the water
  • 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

  the leaf-like branches are round

  Specific leaf type

  • the leaf is divided into two equal parts which in turn are divided into two further parts; each of these parts are divided and each of these may be further divided
  • the leaf is divided into two equal parts; these parts may also be divided into two further parts

  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 blade edges are toothed

  Underwater leaf blade shape

  • the underwater leaf blade is capillary (very fine and hair-like)
  • the underwater leaf blade is linear (very narrow with more or less parallel sides)

  Underwater leaf blade width

  Up to 0.5 mm

  Underwater leaf length

  15–20 mm

  Underwater leaf stalk

  yes

  Underwater leaf tip shape

  the tip of the underwater leaf is acuminate (tapers to a long, thin point)

  Veins in floating leaf

  0

• Place

  Habitat

  aquatic

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • in lakes or ponds
  • in rivers or streams

• 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

From the dichotomous key of Flora Novae Angliae