Turbinicarpus talk.

[DaveW]

Hi All,
Just a reminder of the British Mammillaria Society Turbinicarpus ZOOM talk at 8 pm GMT tonight Thursday 14th December. Those in other time zones need to Google for a time converter from GMT to your time. These talks are live and not recorded so can only be viewed at the time stated. The email from Kathy says:-

Welcome to our last zoom meeting of 2023 for any of you interested in Turbinicarpus this is the 2nd part of Rob Stevenson's Talk. We had the 1st part last year which those of you who were present certainly enjoyed very much, as some of you took the trouble to inform me afterwards. So please make the effort to join us on Thursday evening next week for a very informative talk on this beautiful genus. Which I'm sure we have all made space for a few of them in our greenhouses.

Rob has been growing cacti for around 45 years and joined the NCSS in 1980. Currently, his collection is focused largely on Mexican cacti. He has held the Plant Heritage National Collection status for Turbinicarpus in the past. However, he is no longer involved with Plant Heritage but still has the same collection, consisting of approximately 3ft ×16ft (0.9m × 4.9m) of greenhouse bench.

Following on from Rob’s very successful talk last year on Turbinicarpus, part two will cover the genera Kadenicarpus, Rapicactus and Acharagma. The talk will cover all of the accepted species/subspecies and a number of the other ‘names’ which are commonly found in cultivation. Hybrids will also be mentioned.

https://us02web.zoom.us/j/84007977082?p ... YxS1RwUT09

Zlatko Janeba is inviting you to a scheduled Zoom meeting.

Topic: 'Kadenicarpus, Rapicactus and Acharagma' - Rob Stevenson
Time: Dec 14, 2023 08:00 PM GMT

Join Zoom Meeting

https://us02web.zoom.us/j/84007977082?p ... YxS1RwUT09

Meeting ID: 840 0797 7082
Passcode: 172109

[ohugal]

I try to follow a lot of these Zoom talks and think (besides this) BCSS does a great job. Were these also held before the pandemic?
Regarding the lecture of Rob Stevenson, I must say it's confusing. According to Llifle, Turbinicarpus pseudomacrochele is the accepted scientific name, but the International Plant Names Index registers Kadenicarpus pseudomacrochele also as correct. Is it a question of which taxonomist you decide to follow when labeling/naming your plants? When is a certain name outdated?

[DaveW]

I believe it was the pandemic that started all these talks. However people who could not get to branch meetings of Societies or Cactus Clubs in the USA asked for them to continue. The viewers have also now become international as I don't know any that restrict you to being a member of that society?

As long as a name is validly published under the "Rules" you can use it. Classifications however are not mandatory therefore you can use any you like, or even part of one and part of another. Usually it comes down to the one most are using in your circle, but there have always been more than one classification in use around the world at once. The Brits and Americans tend to be "lumpers" (Britton and Rose and Hunt's) the Continentals "splitters" (Backeberg and Lode'). The truth is probably somewhere in the middle since DNA Sequencing has thrown "a hammer into the works" of most older classifications based solely on morphology like Hunt's even though still popular.

Kadenicarpus was used as a subgenus by Donati & Zanovello in their comprehensive book that Rob Stevenson referred to:-

https://www.cactus-mall.com/bookshop/turb.html

https://academic.oup.com/botlinnean/art ... m=fulltext

https://en.wikipedia.org/wiki/Kadenicarpus

[ohugal]

Thanks.

[MrXeric]

I try to follow a lot of these Zoom talks and think (besides this) BCSS does a great job. Were these also held before the pandemic?
Regarding the lecture of Rob Stevenson, I must say it's confusing. According to Llifle, Turbinicarpus pseudomacrochele is the accepted scientific name, but the International Plant Names Index registers Kadenicarpus pseudomacrochele also as correct. Is it a question of which taxonomist you decide to follow when labeling/naming your plants? When is a certain name outdated?

I think Llifle hasn't has been updated in many years, so names are bound to be outdated. I would say a name is outdated when the most recent publication provides a new (or reinstates an old) name. I like checking the checklist of Cactacea at Caryophyllales.org (https://caryophyllales.org/cactaceae/Checklist) for the most recently published names. The authors (Korotkova N. et al.) compile the names based primarily on recent molecular phylogeny studies and classical, morphology based taxonomy when such studies are not available. Here's the Turbinicarpus page: https://caryophyllales.org/cactaceae/cd ... af87315a05.

As Dave mentioned, recent DNA evidence supports splitting Turbinicarpus as previously described into three genera: Kadenicarpus, Rapicactus, and Turbinicarpus. This study (Vázquez-Sánchez et al. 2019) shows that Turbinicarpus in the strict sense shares a common ancestor with Ariocarpus, but that common ancestor shares a common ancestor with Kadenicarpus, providing a degree of separation. Morphologically the differences are subtle and require a microscope: Kadenicarpus differs in its seed microstructure of the testa (smooth microrelief vs striate in Turbinicarpus) and the stems have xylem fibers in the cortical bundles (missing in Turbinicarpus). More interesting, I think, is genetically how far removed Rapicactus is (more closely related to Acharagma, Lophophora, and Obregonia), suggesting that it originated from an evolutionary line independent of Turbinicarpus.

[ohugal]

Thank you for elaborating on the topic. It helps to know why genera/species are being renamed/recategorized. I'll bookmark the website you mentioned. Seems interesting.

[Tom in Tucson]

I try to follow a lot of these Zoom talks and think (besides this) BCSS does a great job. Were these also held before the pandemic?
Regarding the lecture of Rob Stevenson, I must say it's confusing. According to Llifle, Turbinicarpus pseudomacrochele is the accepted scientific name, but the International Plant Names Index registers Kadenicarpus pseudomacrochele also as correct. Is it a question of which taxonomist you decide to follow when labeling/naming your plants? When is a certain name outdated?

I think Llifle hasn't has been updated in many years, so names are bound to be outdated. I would say a name is outdated when the most recent publication provides a new (or reinstates an old) name. I like checking the checklist of Cactacea at Caryophyllales.org (https://caryophyllales.org/cactaceae/Checklist) for the most recently published names. The authors (Korotkova N. et al.) compile the names based primarily on recent molecular phylogeny studies and classical, morphology based taxonomy when such studies are not available. Here's the Turbinicarpus page: https://caryophyllales.org/cactaceae/cd ... af87315a05.

As Dave mentioned, recent DNA evidence supports splitting Turbinicarpus as previously described into three genera: Kadenicarpus, Rapicactus, and Turbinicarpus. This study (Vázquez-Sánchez et al. 2019) shows that Turbinicarpus in the strict sense shares a common ancestor with Ariocarpus, but that common ancestor shares a common ancestor with Kadenicarpus, providing a degree of separation. Morphologically the differences are subtle and require a microscope: Kadenicarpus differs in its seed microstructure of the testa (smooth microrelief vs striate in Turbinicarpus) and the stems have xylem fibers in the cortical bundles (missing in Turbinicarpus). More interesting, I think, is genetically how far removed Rapicactus is (more closely related to Acharagma, Lophophora, and Obregonia), suggesting that it originated from an evolutionary line independent of Turbinicarpus.

Thanks for informing us on this finding. By astute visual observation of the 3 validly published sections (my preferred generic separation) these genera are somewhat obvious, but the results of this study are fascinating, and provide further evidence for the current state of classification.