Potamogeton cheesemanii

Pondweed at Watson, ACT

Request use of media

Identify this sighting

Potamogeton cheesemanii BettyDonWood 19 Feb 2019
Potamogeton sulcatus BettyDonWood 19 Feb 2019
Potamogeton cheesemanii JaneR 19 Feb 2019

Please Login or Register to identify this sighting.

User's notes

urban wetland, receiving overflow from Billabong Wetland, Watson. Fringed by Bolboschoenus ?medianus. Potamogeton growing with Egeria densa and Vallisneria australis, all in flower: in water about 75 cm deep; heavy epiphytic load.

3 comments

   19 Feb 2019
The leaves appear to be too big for cheesemanii and the number of flowers in the inflorescence too many. The Vicflora key: cheesemanii - floating leaves 0.8-5 cm long, 1-3.5 cm wide, inflorescence usually fewer than 20 flowers; sulcatus - floating leaves 4-8 cm long, 3-5.5 cm wide; inflorescence usually more than 20 flowers. Please comment.
   19 Feb 2019
Yes, I used the Vic key (on-line version updated 2014 which gives slightly different range leaf size for cheesemanii, not as small as 0.8 cm). Specimen taken, currently being pressed.

Floating leaves are 4.6 cm long x 2.9 cm wide, and have 18 veins, excluding central.
Submerged leaves (which are a bit decayed and disintegrated) were up to 10 cm long x 2.5 cm wide, and have 12 veins excluding central (but not very distinct).
Inflorescence appears to have about 24 flowers, and is 2.2 cm long.

Floating leaf size fits either species but vein count matches cheesemannii better. Submerged leaf size fits better with sulcatus, vein count not helpful. Inflorescence number of flowers is just on range for cheesemanii (12-24) but fits sulcatus better (20-60), however overall size fits cheesemanii (1.0-2.5 cm) better than sulcatus (3.2 - 5.0 cm).

There wasn't a clear separation, and I suggested cheesemanni because of vein count, and inflorescence length.
   20 Feb 2019
Like a lot of theses new species, specimens from outside the area of collectiom when the original paper was written can often fall between, which suggests they should not have been separated in the first place.
The length I mentioned of 0.8 cm is in the Vicflora key, which separates sulcatus from two other species. The Vicflora article on cheesemanii states the length is 1.5-5 cm..

Please Login or Register to comment.

Location information

Sighting information

  • 16 - 100 Abundance
  • 18 Feb 2019 04:07 PM Recorded on
  • JaneR Recorded by
  • Yes In flower

Collections

Species information

Record quality

Quality score 6 / 7
  • Images or audio
  • More than one media file
  • Verified by an expert moderator
  • GPS evidence of location
  • Description
  • Additional attributes
  • Nearby sighting(s) of same species
847,339 sightings of 23,782 species from 16,199 members
NatureMapr is developed by at3am | Made and hosted in Australia | privacy | CCA 3.0