Myriophyllum alterniflorum

Growing form

Perennial submerged aquatic herb.

Size

50–100 cm long.

Stem

The stem is very slender, procumbent, with a reddish yellowish tint. Occasionally, there are individual short tubercles at the margin of the leaf bases.

Leaf

The leaves are arranged in whorls. A whorl consists of four leaves. The leaves are 1–2.7 cm long, reddish or bluish. The leaves are sessile. The lamina is pinnately parted. There are 3–9 pairs of lobes, arranged rather densely, and the lobes are typically short, thin and flaccid.

Flower

The inflorescence is emerged above water surface and drooping. The lowest flowers are arranged in whorls and the uppermost flowers are alternate. The most proximal flowers are located at the leaf axils. The flowers are sessile, small, unisexual. Each whorl of the flower consists of four floral leaves. The staminate flowers are located above the pistillate flowers. The bracts are shorter than the flowers and serrulate.

Fruit and seed

The fruit is a schizocarp. The mericarps are drupe-like.

Source: Pinkka e-learning: Botanical excursion to Lammi - Hazel grove and herb-rich forest vegetation by the lake Pääjärvi, herb-rich forest slope on the hill Linnavuori. CC BY 4.0

The map represents observations of this taxon, but it may not be used as a distribution map.

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Observations
  • Total squares
Checklist
MR.1
Scientific name
Myriophyllum alterniflorum
Author
DC.
Vernacular names
  • ruskoärviä (Finnish)
  • hårslinga (Swedish)
Identifier
http://tun.fi/MX.39119
Taxon rank
species
Occurrence in Finland
Collected from Finland
Status in Finland
  • AOV - spontaneous, old, resident
Regulatory Status
  • Vascular plants – SUMI Project 2022 ?
  • Regionally Threatened 2020 - 1a Hemiboreal, Åland ?
Finnish Regional Red List Category
  • 2019 LC – Least Concern
  • 2010 LC – Least Concern
  • 2000 LC – Least Concern
Expert
  • Pertti Uotila
DNA barcode sequences
Myriophyllum alterniflorum
13 public records
Informal groups
  • Vascular plants
  • Plant life forms
  • Aquatic plants
  • Elodeids