Balsamorhiza identification
B. hookeri - common, foxtail leaves, https://www.inaturalist.org/observations/115263062
B. sagittata - large, very common, https://www.inaturalist.org/observations/152379363
B. hookeri - common, foxtail leaves, https://www.inaturalist.org/observations/115263062
B. sagittata - large, very common, https://www.inaturalist.org/observations/152379363
Comentários
I remember we discussed differences between B. sagittata and B. careyana - I think B. sagittata involucre was woolier as in the photo:
https://burkeherbarium.org/imagecollection/photo.php?Photo=wtu122667&Taxon=Balsamorhiza%20sagittata&SourcePage=taxon
Oh yes, John is entirely correct and that is the criterion I use. If a flower bract looks intermediate I just leave them at the genus level. careyana is also more common in lowlands and further south but there is overlap in range.
Also apparently B. careyana often apparently has leaves that feel like very fine sandpaper and B. sagittata leaves are soft.
My current understanding is that B. careyana is found hot dry canyons and valleys in the Artemisia zone and B. sagittata is in cooler moister sites along the Pinus ponderosa zone. The type specimen of B. careyana is with with a multi-flowered inflorescence. The presence of multiple heads per stock suggest B. careyana. Observation 25604391 appears to be identical to the holotype. Although, the type specimen indicated Idaho the label indicates "sandy plains" and considering the date there may have been confusion on the location. The type location is unknown but observations from the area along the Columbia River suggest this is likely the type location.
The Artorhiza appear to have no taxonomic reproductive boundaries and may be considered a symgamion. This condition suggests that there is a large amount of Balsamorhiza in the eastern Columbia River area that is hybrid between Q. careyana x sagittata with individual specimens exhibiting intermediate forms.
Yes I generally agree, although B. careyana seems to get up into some of the cooler areas around Yakima.
I hadn't considered careyana-sagittata hybrids. Does "symgamion" mean that they interbreed to extent that they might not be distinct species? It seems to indicate same gene pool or something of the sort.
I misspelled syngameon and would refer you to the link for an overview. The Project Artorhiza is a look at the taxa involved in the western states and B.C.. The term is over a hundred years old and is being studied in the Genus Quercus. Recognizing hybrids is an art based on recognizing intermediate forms as provided by Tucker, 1990.
Thanks for the pointers and syngameon makes sense. If there are no reproductive barriers (hybrids fully fertile and productive) then how would they maintain separate gene pools? There is population genetics theory that says it would be difficult (but possible), unless the situation is temporary (for example previous allopatric populations that are merging).
There is a theory that the }species" is an ecologically adapted genome. Aldhebiani 2018 provides a summary of the various species concepts. The work of Van Valen 1976 suggested the concept. The study of Benson et.al. 1967 looked at the ecological sorting of Quercus douglasii x turbinella (Q. john-tuckeri). It appears that hybridization is a genetic mechanism testing the terriane for population expansion. There appears to be gene flow but the core genetic component for the local condition remains limited by selection. In the Puget-Willamette Trough both Q. garryana and B. deltoidea populations have originated from a Holocene range extension. The name(s) we use is a designation for forms of a much larger biological reproductive species.
Right, makes sense. I am familiar with most species concepts but the Van Valen idea was new to me.
I am studying "species" ranges using iNat data, but so far I have used only the species definitions they use, which I imagine are an amalgam of various theories dependent on exactly who last worked on what the species are. I tend to assume they are static over the short term (probably unwisely!). Obviously where there are fertile hybrid zones those conditions will change with time, perhaps even over a relatively short time if previously separated populations have come back into contact, say since the last ice age.
Do you think the Balsamorrhiza species are in some sort of stable state? That is, there is careyana - sagittata hybridization but it remains localized enough that it isn't going to fully merge the gene pools, at least in the near term? Selection will surely play a role as well as location and hybrizidation rates, so I imagine it is complex and hard to be sure.
They are stable to the extent of a stable climate. The PNW has been in a cooling trend, now being reversed, as there there was a post glacial temperature spike. In the Cascades that has resulted in the isolation of Q. garryana, and Balsamorhiza in small islands. A long term warming will change the range. From the human lifetime perspective the current range appears to be stable. The zones of hybridization in locations of sympatry are the locations where genetic recombination is at the largest rate and the location of range boundary testing is occuring.
Q. garryana has expanded expanded it's range in the last 34-6k years the Willamette-Puget Trough and Cascade east slope populations are of two different chloroplast haplotypes. These are two different seed line from SW Oregon and California. I think this age range sets some estimate on stablity.
Adicionar um Comentário