Content Author Object Flagger Flag Created Reason Resolved by Resolution
kai_schablewski prickly hawkweed (Pilosella horrida) twr61 Mon, 07 Oct 2019 14:21:58 +0000

POWO appears to be mistaken in placing this taxon in Pilosella

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POWO appears to be mistaken in placing Hieracium horridum in genus Pilosella. Hieracium horridum is endemic to western North America (California, Oregon, Nevada). All of the references I have been able to find online agree that Pilosella is an old world genus which is represented by several exotic and invasive species in North America.
Current regional floras covering the area where Hieracium horridum is found all agree on placing it in genus Hieracium. These floras do also place invasive species in genus Hieracium, but note that others consider them to be part of genus Pilosella.
Flora of North America (2006) http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250066944
Jepson eFlora (2012) http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=3509
Oregon Vascular Plant Checklist (2017) http://www.oregonflora.org/family_treatments/Asteraceae.pdf
Flora of the Pacific Northwest (2018)

Bräutigam & Greuter (2007) A new treatment of Pilosella for the Euro-Mediterranean flora https://www.bgbm.org/sites/default/files/documents/wi37-1Braeutigam%2BGreuter.pdf
Gaskin & Wilson (2007) Phylogenetic Relationships Among Native and Naturalized Hieracium (Asteraceae) in Canada and the United States Based on Plastid DNA Sequences https://www.cals.uidaho.edu/hawkweed/pdf/Gaskin%20Wilson%20phylogeny%202007.pdf
Moffat et al (2015) Morphology delimits more species than molecular genetic clusters of invasive Pilosella https://bsapubs.onlinelibrary.wiley.com/doi/pdf/10.3732/ajb.1400466
Wilson (2007) Key to Identification of Invasive and Native Hawkweeds (Hieracium spp.) in the Pacific Northwest https://www2.gov.bc.ca/assets/gov/environment/plants-animals-and-ecosystems/invasive-species/publications/key_to_identification_of_invasive_and_native_hawkweeds_in_the_pacific_northwest.pdf

Posted by twr61 over 1 year ago (Flag)
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Hi @twr61, thanks for taking a look into this and sorry it's taken so long for someone to respond. Going through some of these references:

Flora of North America (2006) - lumped concept of Hieracium
Jepson eFlora (2012) - lumped concept of Hieracium
Oregon Vascular Plant Checklist (2017) - lumped concept of Hieracium, as is oregonflora.org (2020), still
Flora of the Pacific Northwest (2018) - idk
Bräutigam & Greuter (2007) A new treatment of Pilosella for the Euro-Mediterranean flora - doesn't cover North American flora
Gaskin & Wilson (2007) Phylogenetic Relationships Among Native and Naturalized Hieracium (Asteraceae) in Canada and the United States Based on Plastid DNA Sequences - lumped concept of Hieracium, with Pilosella as a subgenus
Wilson (2007) Key to Identification of Invasive and Native Hawkweeds (Hieracium spp.) in the Pacific Northwest - lumped concept, but doesn't list horrid* in H. subg. Pilosella, but rather H. subg. Chionoracium. Of the species listed on page 6, Table 1, POWO places them all in Pilosella, except for H. bolanderi, H. greenei (syn. H. traillii), H. longiberbe, and H. parryi

Gaskin & Wilson 2007 looks most useful of these since it seems to indicate horrid* is most closely related to H. canadense (syn. H. umbellatum), H. parryi, and H. bolanderi, all of which POWO lists as being in Hieracium and not Pilosella.

additional:

VASCAN does note one Pilosella species as native to North America, Pilosella tristis: https://data.canadensys.net/vascan/taxon/31903

I wonder if there is some more recent treatment that looks at the delineation of the former Hieracium subgenera Pilosella vs. Chionoracium?? I did a quick search but wasn't able to find one. @convallaria1128 @kai_schablewski @choess any insight?

Posted by bouteloua 6 months ago (Flag)
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I sent a message to POWO today asking for clarification. Still not able to find any more recent treatments of these genera that might lead to any insight in my searches. It may be that we'll need to swap it back into Hieracium horridum (which is kind of annoying/messy).

I've documented several similar cases here: https://www.inaturalist.org/taxon_framework_relationships/316835

Posted by bouteloua 4 months ago (Flag)

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