Ludwigia sp.

Water-primrose or water-purslane at Fyshwick, ACT

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Identification history

Ludwigia sp.	16 May 2018	michaelb
Ludwigia sp.	16 May 2018	michaelb
Potamogeton sp.	30 Apr 2018	KenT
Unidentified	30 Apr 2018	Christine

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9 comments

BettyDonWood wrote:

1 May 2018

I do not think it is Potamogeton, which has submergered stems, and the submerged leaves of which are narrow and translucent. I do not recognise it at all. Perhaps something from dumped garden waste.

KenT wrote:

1 May 2018

I felt Potamogeton was a bit of a long shot, I wish it had visible flowers. It has some similarity to some images online of floating primrose willow (Ludwigia peploides) but not to any of the Ludwigia images on CNM. One image (p38, top right) of “Recognising Water Weeds - Plant Identification Guide“ https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0007/329308/041209-DPI-RWW-PLANT-GUIDE.pdf for Ludwigia peploides subsp. montevidensis looks a bit like it but this image also looks different to other examples of this species, otherwise this would have been my alternative suggestion.

member211 wrote:

12 May 2018

I agree this is not Potamogeton and agree it is not quite like Ludwigia peploides subsp. montevidensis.
However it does look like Ludwigia peploides, see:
https://www.arkive.org/creeping-water-primrose/ludwigia-peploides/image-G142368.html
https://www.swcd.net/invasive-noxious-weeds/water-primrose-aka-ludwigia/
http://www.backyardnature.net/n/h/primwill.htm
http://www.freenatureimages.eu/plants/Flora%20J-N/Ludwigia%20peploides/index.html#Ludwigia%20peploides%201%2C%20Saxifraga-Rutger%20Barendse.jpg

member211 wrote:

12 May 2018

PS: member211 is a pseudonym Michael Bedingfield uses for testing CNM software.

AaronClausen wrote:

12 May 2018

Hi member211, how are you today?

michaelb wrote:

12 May 2018

He's fine, but adjusting to the sudden arrival of winter and snow on the mountains !

BettyDonWood wrote:

12 May 2018

Michael’s link caused me to check on Ludwigia more carefully. Vicflora states that the leaves can rarely be orbicular. The CABI site states that early growth resembeles a rosette of rounded leaves growing on the water surface, with alternate leaves later. https://www.cabi.org/isc/datasheet/31673
There is a photo of Ludwigia peploides subsp. peploides in EOL showing this character, which is not mentioned in any of the Australian sites for subsp. montevidensis. https://www.cabi.org/isc/datasheet/31673
However, there is no evidence of lanceolate leaves in this photo.

MichaelMulvaney wrote:

16 May 2018

Stephen Skinner of the NSW Botanic Gardens said that the phot doesn't contain enough information to determine which Ludwigia it is but…1. L. peploides var montevidensis is the one that is reported to be local, and was the one I frequently encountered; 2. Without flowers they are often difficult to separate…L. palustris has sessile flowers in the axils of the leaves, L. peruviana has shortly petiolate flowers in the axils of the leaves and L. peploides has flowers on long petioles in the axils of the leaves; and 3. L. peploides is native, the other two are notifiable weeds.

michaelb wrote:

16 May 2018

Thanks Michael M

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