Talk:Mahonia

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Accepted genus?
Many databases including Wikispecies claim Mahonia is a synonym of Berberis. As far as I know, Tropicos and WCSP (in review) still accept Mahonia as a genus, but keep an eye out for updates.--MCEllis (talk) 07:11, 17 February 2016 (UTC)


 * It looks like to me that Tropicos now out of date http://www.theplantlist.org/tpl1.1/search?q=Mahonia There is a big red "superseded" over the logo. Going to http://www.worldfloraonline.org/search;jsessionid=69C5B956098B7CCC026F1F8635380107?query=Mahonia now it looks like all the genus is no longer accepted since all results are synonyms for *Berberis*. Unless someone has a good objection I'm going to change the text to some variety of "This is historic and no longer commonly accepted." MtBotany (talk) 20:17, 23 December 2022 (UTC)

The best classification of species currently in Mahonia
I think everyone who knows anything about the history of Mahonia and if it should be separated from Berberis knows how complex the arguments have been. I was inspired to write this today by seeing that NatureServe lists Mahonia repens as Berberis repens and once again wading into the thorns looking for clarity.

The most recent paper on the genetics of of the taxon seems to be "Why Mahonia? Molecular recircumscription of Berberis s.l., with the description of two new genera, Alloberberis and Moranothamnus" by Chih-Chieh Yu and Kuo-Fang Chung. I have not yet been able to find access to this paper and I have only found Alloberberis and Moranothamnus in World Plants Alloberberis Moranothamnus. Plants of the World Online and World Flora Online continue to list Berberis as the valid classification of all Mahonia species. With this confusion, what should Wikipedia do?

As I see it there are three options:
 * 1. Do nothing leaving things as they have been traditionally classified, using USDA and/or VASCAN as the reference, but having a notice on all of the talk pages to reopen this issue before rewriting the classification or moving pages.
 * Advantage: simplest option, very little work needed for now.
 * Disadvantage: May not be following the best possible taxonomic information and creating some confusion
 * 2. Follow a majority of up to date books and other databases, changing species to Berberis for now and back to Mahonia when/if there is majority of World Plants, WFO, and POWO.
 * Advantage: Seems to agree with majority of new sources and maintain consistency with usually following POWO's classification.
 * Disadvantage: More work now, and possibly more work later when/if a majority change back to Mahonia and/or the newest circumspection.
 * 3. Follow what seems to be a well researched paper. Make a note that we will follow World Plants in regard to family Berberidaceae. Move the few plants that need it to Alloberberis or Moranothamnus.
 * Advantage: Very little work now. Seems like it is likely to be where classification is headed.
 * Disadvantage: Disagrees with many commonly used sources and may result in more work later if the majority of botanists decide that Berberis is the way to go after all.

I am very mildly inclined towards option 3., but I am very much open to being convinced by evidence or logical argument that one of the other two options is the way to go for now here on Wikipedia. Opinions? Suggestions? More information? 🌿MtBotany (talk) 20:31, 1 November 2023 (UTC)


 * , Wiley publications are available via The Wikipedia Library which is something you should be able to access. POWO has 9 species of Mahonia that are listed as "unplaced" (e.g. M. angustifolia), as well as some nothospecies. "unplaced" generally means that something is regarded as a distinct species, but no combination for it has been published in a genus that POWO wants to recognize. POWO sometimes lumps genera that may not be of any particular interest to anybody working at Kew, but which continue to be recognized by local botanists in the regions where the species occur (I think all the unplaced Mahonia species are from China). Since the locals reject the lumping, there is really nobody who is interested in publishing the combinations in the genus POWO wants to recognize.


 * Yu & Chung do not provide a comprehensive list of Mahonia species. The list of species in this article claims it is sourced to Tropicos, but I think it may actually be sourced the The Plant List (which is down at the moment). My inclination would be not to lump Mahonia, but there is a problem in not having an up-to-date comprehensive list of Mahonia species. Plantdrew (talk) 21:19, 1 November 2023 (UTC)
 * I think I figured out what I was doing wrong in regards to Wiley, I needed to access the collection directly instead of relying on searching "all of my collections" from the search the library at the top. Glad I kept poking so I'm now going to read the whole paper and have a better idea of what is going on. 🌿MtBotany (talk) 22:01, 1 November 2023 (UTC)
 * Mahonia is no longer an accepted genus. It and all its species should be redirected, moved or merged to Berberis and its species immediately. Abductive  (reasoning) 07:43, 3 November 2023 (UTC)
 * @Abductive @Plantdrew Well, seems like moving to Berberis is the best option for now. This might mean more work later, but IF the new Alloberberis and Moranothamnus along with Mahonia end up being accepted it could be five to ten years before we have a comprehensive list available. Right now I'm going to rewriting the page to reflect that it is of historic interest and that while USDA, etc. still list plants in Mahonia that Berberis is where to find current information. 🌿MtBotany (talk) 16:11, 4 November 2023 (UTC)
 * A more recent 2022 paper illustrates the issues with the proposed splits. It is unfortunate that they only sampled 60 taxa (of the 786 accepted taxa in Berberidaceae or less than 10%) which does not seem sufficient for it to be the last word on this.
 * There also seems to be a conflict in the statement that “our phylogenomic data also support the classification of 19 genera, .... that are morphologically and evolutionarily distinct”
 * and the statement that “Alloberberis and Moranothamnus could have resulted from reciprocal hybridization between Berberis and Mahonia” and “the support for the monophyly of Mahonia is low “ as this repeated hybridization would indicate that they are not evolutionarily distinct. Weepingraf (talk) 22:16, 18 November 2023 (UTC)
 * @Weepingraf Thanks for following up with more information, that is an interesting paper.
 * I expect that this topic will be revisited many times and all we can do as an encyclopedia is follow what seems to be a majority of botanists at any given time while giving due weight to contrary points of view. Perhaps a future study will more firmly establish if Mahonia is synonymous with Berberis or not to the satisfaction of most botanists, but I'm content to have us following POWO for now in this case.
 * I've been biting off a bit at a time of moving the accepted Mahonia species to Berberis. I putting a "Taxonomy" section on each Mahonia article that does not have one briefly explaining the history of the controversy and how the species was originally described and by who. I've run across a few that are "unchecked" and do not have a "Berberis" synonym yet, but not many. 🌿MtBotany (talk) 23:17, 18 November 2023 (UTC)
 * Their hypothesis seems to be that Alloberberis and Moranothamnus originated by hybridisation between stem-Berberis and stem-Mahonia species, which leaves crown-Berberis and crown-Mahonia monophyletic. Lavateraguy (talk) 08:49, 28 November 2023 (UTC)
 * @Lavateraguy The genetic relationship information is fairly convincing, the question that has not yet been settled is if the distinct linage is distinct enough to be considered a separate genus. I'm somewhat in favor of Mahonia being a distinct genus, but I don't know enough to say if this is provincial prejudice in favor of what I'm used to or if I'm seeing a difference that ought to be taxonomically recognized. 🌿MtBotany (talk) 16:18, 28 November 2023 (UTC)