The Genus Mammillaria
The genus, Mammillaria Haw., was named and described by Adrian Hardy Haworth in Synopsis Plantarum Succulentarum in 1812. It is one of 144 currently accepted genera in the Cactaceae family. The family, Cactaceae Juss., was named and described by Antione Laurent de Jussieu in Genera Plantarum in 1789.
As of December 12, 2020, Plants of the World Online lists 165 species in the Mammillaria genus, which does NOT include, varieties, forms, and subspecies which are for the most part are listed as synonyms.
Some of the best, nicest, easiest to grow, and most collected cacti are in species are Mammillaria species. For the most part, if you purchase a Mammillaria with a label you can check with Plants of the World Online to see if the name on the label is an accepted name or now a synonym of a different species. That happens a lot and it can get confusing at times. Once you have the name figured out, you can go to the LLIFLE (Encyclopedia of Living Forms) and find more information about your plant. HOWEVER, you may find it under a synonym… The website is HUGE and has a lot of information and I am sure it is hard to keep up with name changes. If you bring home an unlabeled plant and want to identify it, there are several Facebook Groups with members that are pretty good. One of the best ways is to get on the CactiGuide, sign up to the forum, and post photos (top, sides, close-ups, etc.) in the category for Cactus ID.
Most Mammillaria species are “variable”, which is a word I am beginning to dislike A LOT. Descriptions may not “exactly” fit your plant. Spine count and size are variable within the species which led to a multitude of species, forms, subspecies, and varieties being named for the same species. Small plants (juveniles) grow and change somewhat over time as well. Spines get longer, they grow wool and hair in the axils (or it gets longer). You may have a wooly species with short hair then bring home other plants of the same species that have long hair and just a small amount of wool or even none at all. Some species may have no central spines but a variant of it may have 1-3… In the wild, a group of plants may have the same features, but in another area the same species may look completely different. Most cultivated plants (grown in mass quantity and sold at Wal-Mart, Lowe’s, etc. are very small and have to “grow into” what they will eventually look like. If you are fortunate enough to find plants with labels you are already headed in the right direction, however, the industry trend to sell plants merely labeled “CACTUS” is a frustrating start.
When I first started blogging in 2013, I began using version 1 (2010) of The Plant List for plant name research. At that time, The Plant List named 176 accepted species plus 126 accepted infraspecific names. There were 497 synonyms of species rank plus another 129 infraspecific names. There were also a total of 430 unresolved names. When version 1.1 came out in September 2013, I had several name changes to make. The accepted species increased from 176 to 185 and infraspecific names decreased from 126 to 93. The list of synonyms of specific rank also decreased from 497 to 358. The infraspecific species synonyms changed from 129 to 161. Also, the list of unresolved names increased from 430 to 448.
The Plant List wasn’t updated since version 1.1 in 2013 and I was told by a member of Kew that it was no longer maintained. He gave me a link to their new website called Plants of the World Online. They are still uploading data and expect to be finished with that process in 2020. Of course, with new species being found and all the testing going on, the updating process will always be ongoing.
As I am updating the pages for the Mammillaria in my collection in November 2020, Plants of the World Online lists 164 accepted species of Mammillaria. Of course, over time, that number will continue to change. It doesn’t list a total of infraspecific names or synonyms for the entire genus as The Plant List did, but you can click on each species to find that information. Mostly, the intraspecific names are considered synonyms of the species which is very confusing…
I also use several other websites for plant name for cactus and author research including Llifle (Encyclopedia of Living Forms), CactusGuide by Daiv Freeman, Dave’s Garden and a few others. For author name research I use The International Plant Name Index through Plants of the World Online and Tropicos (a division of The Missouri Botanical Garden). I still refer to The Plant List, even though it is no longer maintained, to see progress. A fairly new site, World Flora Online, is supposed to take the place of The Plant List. They uploaded data from The Plant List even though the site hadn’t been updated since 2013. They are supposed to upload current data from Plants of The World Online, but as of December 2020 I didn’t think they have done it yet… So, imagine a new plant database with outdated names… The Plant List is a great site, so I don’t know why they didn’t just update and improve upon it instead of launching a new site.
There is the ongoing dilemma of the industry mislabeling plants and sites like Llifle and the CactusGuide are very useful tools to make a positive ID. If you are still confused, like I mentioned, post photos on a Facebook group or get on the CactiGuide forum.
The following Mammillaria pages are about my journey with the Mammillaria companions I have been blessed to know, There will be more to come.
The links below will provide you with additional information and there are other links on each page about their species. The links below will take you directly to information about the genus Mammillaria.
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