Pondweed at Majura, ACT
Identification history
| Potamogeton sp (cheesemanii or sulcatus) | 18 Jan 2021 | MichaelBedingfield | ||
| Potamogeton sp (cheesemanii or sulcatus) | 18 Jan 2021 | MichaelBedingfield | ||
| Potamogeton sulcatus | 17 Jan 2021 | MichaelBedingfield | ||
| Unidentified | 16 Jan 2021 | JaneR |
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User's notes
Plants mostly stranded on wet muds by falling water levels: occurring infrequently in this dam, only on southern shore.
13 comments
JaneR
wrote:
17 Jan 2021
I assigned it to Potamogeton cheesemanni rather than P. sulcatus due to number of longitudinal veins being two few for P. sulcatus, and number of flowers in spike being too few also. But leaf width length was indeed more like P sulcatus
MichaelBedingfield
wrote:
17 Jan 2021
Do you think this sighting ID is correct for Potamogeton cheesemanni ?:- Potamogeton cheesemanii (Pondweed)
It is different from this one:- Potamogeton cheesemanii (Pondweed)
It is different from this one:- Potamogeton cheesemanii (Pondweed)
JaneR
wrote:
17 Jan 2021
Hi Michael,
How do you decide what characteristics to rely on ?
I can see that the wider more lime-green leafed plants look different from the narrower, darker plants; but wonder if that is phenological differences: early season v later older plants.
I have just checked a specimen collected from the same dam on 9 Dec 2020. Overlapping characteristics are leaf size (3.7x2.6, 5.8x3.4 - either species); rounded apex; number of flowers is 20, or 21. Characteristics that fit P. cheesemanii are: longitudinal veins are 15, and infructescence is 1.8 cm long.
Sighting 4198017 also looked like it should be P.sulcatus but had metrics that better suited P. cheesemanii.
Sighting 4352668 was earlier in the season; but has only 9-11 longitudinal veins (no specimen collected so have no other info).
I don't know how to resolve this - ??
How do you decide what characteristics to rely on ?
I can see that the wider more lime-green leafed plants look different from the narrower, darker plants; but wonder if that is phenological differences: early season v later older plants.
I have just checked a specimen collected from the same dam on 9 Dec 2020. Overlapping characteristics are leaf size (3.7x2.6, 5.8x3.4 - either species); rounded apex; number of flowers is 20, or 21. Characteristics that fit P. cheesemanii are: longitudinal veins are 15, and infructescence is 1.8 cm long.
Sighting 4198017 also looked like it should be P.sulcatus but had metrics that better suited P. cheesemanii.
Sighting 4352668 was earlier in the season; but has only 9-11 longitudinal veins (no specimen collected so have no other info).
I don't know how to resolve this - ??
MichaelBedingfield
wrote:
18 Jan 2021
My botanical skills are limited, so I can't resolve it. We need trained botanist. The problem of differentiating the two species will continue, so I have added a new name to the species list "Potamogeton sp (cheesemanii or sulcatus)". If we can't solve the problem we can classify it that way:- https://canberra.naturemapr.org/species/46052
JaneR
wrote:
18 Jan 2021
that is an excellent solution, responsible and practical. if resolution requires detailed examination, then ID down to species will otherwise always be a stumbling block for CNM.
JaneR
wrote:
18 Jan 2021
Should this be applied retrospectively to other Potamogeton contentious ID ?
MichaelBedingfield
wrote:
18 Jan 2021
I've re-ID Potamogeton sp. & moved a few into the new grouping, only 2 left:- https://canberra.naturemapr.org/species/22322
Tapirlord
wrote:
14 Feb 2023
My understanding is that p.sulcatus has broader leaves ovate-elliptic as opposed to p.cheesemanii which will have lanceolate-ovate (never elliptic). p.sulcatus has longer infloresence with crowded flowers (usually greater than 20), while p.cheesemanii has short infloresence (under 3cm) & less crowded infloresence. as jane says p.sulcatus is said to have more than 20 veins per leaf but this can be difficult to determine from photos. i would say considering everything this is most likely p.sulcatus while the sighting you reference michael (Potamogeton cheesemanii (Pondweed)) is certianly p.cheesemanii.
Tapirlord
wrote:
14 Feb 2023
Also I seem to be having issue with CNM comments (I can't have capitals & hyperlinks in the same comment).
JaneR
wrote:
14 Feb 2023
the counts of veins and flowers on inflorescence were made on actual plant material at the time. These are (for me) stronger characteristics than leaf shape, and so lead me to P cheesemanii: which was a puzzle as leaf shape did look like P. sulcatus.
MichaelBedingfield
wrote:
15 Feb 2023
Hi Ciaran, I agree there is a bug whereby capitals are lost with hyperlinks.
Location information
- Coordinates 149.172189-35.261738
- Altitude 641.1m
- Maps Mount Ainslie
- Places Majura, ACT
Sighting information
- 16 - 100 Abundance
- 16 Jan 2021 12:09 PM Recorded on
- JaneR Recorded by
-
Collections
Plants Other Fresh Water Plants
Additional information
- True In flower
Species information
- Potamogeton sp (cheesemanii or sulcatus) Scientific name
- Pondweed Common name
- Not Sensitive
- Local native
- Non-invasive or negligible
- Up to 778.43m Recorded at altitude
- Machine learning
-
In flower
- External link More information
Record quality
- Images or audio
- More than one media file
- Verified by an expert moderator
- Nearby sighting(s) of same species
- GPS evidence of location
- Description
- Additional attributes
