Landoltia punctata

Spotted Pondweed at suppressed

Landoltia punctata at suppressed - 23 Feb 2022
Landoltia punctata at suppressed - 23 Feb 2022
Landoltia punctata at suppressed - 23 Feb 2022
Landoltia punctata at suppressed - 23 Feb 2022
Landoltia punctata at suppressed - 23 Feb 2022
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Identification history

Landoltia punctata 24 Feb 2022 JaneR
Lemna disperma 19 Feb 2022 Mike

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User's notes

Multiple roots.

4 comments

JaneR wrote:
   19 Feb 2022
The reliable way of distinguishing between Lemna and Spirodela, which are both tiny floating plants, is by checking the number of roots per thallus.
Lemna has 0 to 1, whereas Spirodela has 2 to 18 roots per thallus.

Less reliable (harder to apply consistently) is the number of plants in a group. Spirodela tend to form smaller groups (of 2 to 5 plants) whereas Lemna can form bigger groups (up to 10 plants).

The photo is not conclusive either way, but Lemna is plausible.
Mike wrote:
   24 Feb 2022
Thanks @JaneR for the information on ID. I have added photos showing the multiple roots. Plants in groups of 2-5. Leaves purplish underneath. I can't distinguish veins.
Mike wrote:
   24 Feb 2022
CNM lists Spirodela punctata (renamed) but NSW Flora Online lists Spirodela polyrhiza. Are they the same?
JaneR wrote:
   24 Feb 2022
great photo of the roots: a very nice addition to the sighting. This makes it a Spirodela (now known as Landoltia), rather than Lemna. PlantNet has Spirodela polyrhiza and Landoltia punctata.

it is relatively easy to check for the roots, if you have a stick and the plants are within reach: lift some out, and the roots are apparent draped over the stick.

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Sighting information

  • 1,001 - 10,000 Abundance
  • 23 Feb 2022 04:35 PM Recorded on
  • Mike Recorded by

Species information

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