Rigid Hornwort - Ceratophyllum demersum

Description

Stem flexuous with rigid leaves in whorls of 3 to 8. Leaves dark green 1-2 forked divided into slender toothed segments. Flowers solitary with 8 or more linear petals, female flowers green, male flowers whitish. Fruit a small nut 4-5 mm with basal spines, otherwise smooth.

Similar Species

Ceratophyllum submersum

Identification difficulty
ID checklist (your specimen should have all of these features)

Leaves forked 1 - 2 times

Recording advice

A good image clearly showing the leaf details as well as the plant as a whole.

Habitat

Freshwater habitats, ponds, slow moving rivers and canals rooting in the muddy bottom.

When to see it

Flowers July to September.

Life History

Perennial.

UK Status

Fairly widespread in lowland areas of Britain.

VC55 Status

Occasional and local in Leicestershire and Rutland, but may be abundant where it occurs. The Flora of Leicestershire published in 1988 states that it occurred in 25 of the 617 tetrads.

In the current checklist (Jeeves 2011) it is listed as native; now rarely recorded, but possibly overlooked

Leicestershire & Rutland Map

MAP KEY:

Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map

Species profile

Common names
Rigid Hornwort, Hornwort
Species group:
Wildflowers
Kingdom:
Plantae
Order:
Ceratophyllales
Family:
Ceratophyllaceae
Records on NatureSpot:
13
First record:
27/08/2007 (Dave Wood)
Last record:
25/10/2023 (Pugh, Dylan)

Total records by month

% of records within its species group

10km squares with records

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