Potentilla, Salix, Viola and Eleocharis Updates to the Vascular Plant List –
the Importance of Using Current Taxonomic Keys
January 26, 2017
The SKCDC strives to keep its species lists up to date with the latest accepted taxonomic changes. Four groups that have undergone significant changes and have been updated on the Vascular Plant List are the Potentilla (following the Flora of North America, 2014), Salix (following the Flora of Saskatchewan's Conifers & Catkin-bearing Trees and Shrubs of Saskatchewan, 2016), Viola (following the Flora of North America, 2015) and Eleocharis (following the Flora of North America, 2002). Users can view the Vascular Plant List to see the updated names and ranks for these groups.
Crataegus has also undergone a great deal of change and users may notice that the SKCDC plant list does not reflect these changes. This genus, as well as a few other species of interest, is currently being reviewed by the Botanical Assessment Working Group.
It should be noted that when users are identifying plants in the field (and subsequently submitting data to the SKCDC), the most recent taxonomic keys should be used to determine species identification in order to avoid confusion. The Flora of North America, where volumes have been recently published, is generally considered to be the most updated, accepted information. Many field biologists continue to use their favorite old keys in the field rather than the most current ones and this can cause issues for the quality control of the data. It is appreciated when users fill out the "Identification Source" and "Taxon Name Used in Identification Source" fields in the Species Detection Loadform when submitting observations so that staff can be sure of the intended species identification, otherwise, extra follow up may be needed.
Here are some examples of relatively recent changes (in the SKCDC database) that may cause confusion:
- Potentilla nivea – the older use of this name has been applied to Potentilla arenosa and Potentilla rubricaulis. In the most recent sense of this name, Saskatchewan is not yet verified as part of the distribution (although there is potential for it to occur here). The Flora of North America provides the correct taxonomic key for determining this species.
- Lemna minor – most Saskatchewan observations that were previously being called Lemna minor refer to Lemna turionifera (based on herbarium specimen evidence). L. turionifera is the common Lemna in Saskatchewan, while L. minor is actually rare (S1) and has only one record near Saskatoon. The Flora of North America provides the correct taxonomic key for determining this species.
- Packera plattensis – almost all herbarium specimens from the W.P. Fraser Herbarium that were previously thought to be Packera plattensis have been revised to P. paupercula, therefore P. plattensis is much more rare in Saskatchewan than previously thought. Those familiar with using the name P. plattensis may be inadvertently placing identifications to P. plattensis that actually belong under P. paupercula. The Flora of North America provides the correct taxonomic key for determining this species.
- Corispermum nitidum – while this name was once applied to plants found in Sask., all such material has since been revised to other Corispermum species (generally to C. americanum) and C. nitidum is considered to have never actually occurred in Sask. (it is a European species). Here is a helpful resource of interest: Robson, D.B. 2010. The bugseeds (Corispermum) of the Prairie Provinces. Blue Jay 68: 199-207.
- Eleocharis palustris complex – revisions to herbarium specimens have resulted in changes to the S-ranks. Specimens previously identified as E. uniglumis, E. mamillata and E. macrostachya have been revised to E. palustris, leaving E. uniglumis and E. mamillata with rarer status (S3 and S1 respectively). A single, indeterminate specimen of E. macrostachya exists and is not enough evidence to consider this species as occurring in SK; therefore this species has been removed from the SK Eleocharis list. It does, however, have the potential to occur here and would be rare if found.
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