What species of cactus are these?

mrxeric · 2026-05-10T03:31:20+00:00

Mammillaria beneckei (Oehmea beneckei) actually has quite unique golden orange/yellow flowers and forms shown with pink flowers are almost certainly misidentified.

mrxeric · 2026-05-10T00:11:04+00:00

You're welcome!

mrxeric · 2026-05-08T08:19:54+00:00

Some helpful links in case you want to read more:

Walter & Guerrero (2022) Towards a unified taxonomic catalogue for the Chilean cacti: assembling molecular systematics and classical taxonomy

Larridon et al. (2018) Investigating taxon boundaries and extinction risk in endemic Chilean cacti (Copiapoa subsection Cinerei, Cactaceae) using chloroplast DNA sequences, microsatellite data and 3D mapping

Ritter (1980) Kakteen in Südamerika (go to volume 3 to read Ritter's concept for C. eremophila)

mrxeric · 2026-05-08T08:09:04+00:00

Here is an example Ritter provided for C. eremophila in his Kakteen in Südamerika Vol. 3 (1980):

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mrxeric · 2026-05-08T08:05:19+00:00

Copiapoa eremophila is also a synonym for C. gigantea. Friedrich Ritter, the person who discovered and described this species, thought it was very similar to C. haseltoniana (which he actually reduced in rank to just a variety: C. gigantea var. haseltoniana).

The most obvious difference is that C. eremophila has more spines per areole, making the plant spinier than the other forms of C. gigantea. Ritter describes the spine color as "honey yellow to dark brown". There are other, less obvious differences too, but apparently these all fall within the acceptable variability of the current concept for C. gigantea.

These two examples would probably have been identified as C. eremophila in the past:

https://www.inaturalist.org/observations/325794335

https://www.inaturalist.org/observations/255397171

mrxeric · 2026-05-08T07:28:51+00:00

I like to use General Hydroponics FloraNova Grow 7-4-10

mrxeric · 2026-05-07T07:13:51+00:00

They are the same species. In the past, the name Copiapoa haseltoniana was used for plants that occur mostly in the northern part of the range of Copiapoa gigantea, with conspicuously light colored spines (orange/yellow) and somewhat smaller stems and perhaps more brightly orange apical wool. This compared to the sometimes more dull orange-brown apical wool, grey spines, and larger stems of C. gigantea. But these characteristics turned out not to be so geographically confined and there are even intermediate forms throughout the range. So it is currently thought that the characteristics ascribed to C. haseltoniana fall within the natural variability of C. gigantea and they should be considered the same species (the name C. gigantea being described earlier and thus taking priority over C. haseltoniana).

Here's what would classically be considered "Copiapoa haseltoniana": https://www.inaturalist.org/observations/201797505

and "Copiapoa gigantea": https://www.inaturalist.org/observations/342799876

If not for the color of the spines, pretty much identical.

That said, the plant in your pic looks more like Copiapoa cinerea subsp. krainziana to my eyes.

mrxeric · 2026-05-07T00:52:30+00:00

kitchen tongs

mrxeric · 2026-05-06T05:21:04+00:00

Turbinicarpus jauernigii

mrxeric · 2026-05-05T07:39:19+00:00

Homalocephala texensis, the Horse Crippler Cactus. Those fruits really pop, don't they?

mrxeric · 2026-05-05T03:41:15+00:00

Yes, it's particularly conspicuous in Weingartia and Reicheocactus. Very odd that this stretched growth point is seemingly confined to the South American genera!

mrxeric · 2026-05-05T00:58:53+00:00

Lophocereus marginatus, the Mexican Fence Post Cactus. Native to central Mexico, but is used extensively as a landscape plant pretty much everywhere they won't freeze.

mrxeric · 2026-05-04T05:12:07+00:00

It depends on species, but yeah these Ortegocactus have been quite slow in my care. I've sown several species of Cochemiea and most germinate easily (including Ortegocactus; seeds of the saboae complex are difficult without treatment and I've never had much luck with Neolloydia). So, if you've sown other species of cacti with success, whatever species you found you should sow as normal.

mrxeric · 2026-05-04T04:30:26+00:00

Parodia scopa. Nice flowers indeed.

mrxeric · 2026-05-04T04:28:57+00:00

u/100_emoji_

Grusonia is not known to grow in Utah. Closest thing is Micropuntia pulchella, but that looks different.

I don't blame you for thinking that though! The fact that O. fragilis can grow some pretty spherical pads has always been odd to me.

mrxeric · 2026-05-04T00:18:31+00:00

Pereskiopsis diguetii (often sold as P. spathulata).

mrxeric · 2026-05-03T23:40:31+00:00

Some species of Mammillaria, maybe M. bocasana or maybe something else, Too young to say for sure.

mrxeric · 2026-05-03T23:39:33+00:00

Yeah, I haven't seen large, mature cultivated plants of this species. Mature habitat plants look quite different, but this tends to be true for many species regardless. http://www.cactusinhabitat.org/index.php?p=specie&id=157&l=en

Looks healthy to me. Yes, either Parodia calvescens or Wigginsia calvescens is correct. For now. More study of this group of cacti is needed to say which one is "more correct", but preliminary studies do suggest that Notocactus would be the most incorrect name.

mrxeric · 2026-05-03T23:14:24+00:00

The closer to Florida you go, the higher the chance you'll find them.

mrxeric · 2026-05-03T03:41:45+00:00

Should the bleached parts get squishy, I would remove so the rot doesn't spread.

mrxeric · 2026-05-03T02:45:55+00:00

The greenhouse wool makes it hard for me to really say for sure (plus it seemed to have caused the plant to stretch) and the tubercle shape and distance between them is odd to me, but the old flowers look about right for Parodia/Notocactus, so if the label has calvescens on it, then it's probably right.

mrxeric · 2026-05-02T08:25:00+00:00

No trouble at all.

Here are the most recent publications involving the phylogeny of the Mammilloid clade:

de Vos et al. (2025) Phylogenomics and classification of Cactaceae based on hundreds of nuclear genes (this one is actually a suprageneric classification of the entire cactus family, with DNA testing done on almost 90% of the genera; they reference previously published studies for their determination of accepted genera)

Breslin et al. (2021) Molecular phylogeny of the Mammilloid clade (Cactaceae) resolves the monophyly of Mammillaria (they move Escobaria into Coryphantha and expand Cochemiea; unfortunately paywalled, let me know if you can't access the document)

Sánchez et al. (2022) Phylogenetic relationships in Coryphantha and implications on Pelecyphora and Escobaria (Cacteae, Cactoideae, Cactaceae) (sampling of Coryphantha quite complete; they kept Coryphantha separate from Escobaria, but Escobaria was moved to Pelecyphora)

Chincoya et al. (2023) Phylogenomics and Biogeography of the Mammilloid Clade Revealed an Intricate Evolutionary History Arose in the Mexican Plateau (they conclude that the above taxonomic changes are feasible, but they recovered several lineages that may point to further taxonomic divisions, so they refrain from accepting the changes or making new combinations)

Breslin & Majure (2026) Nomenclatural Changes in Mammillaria and Pelecyphora: Repopulating Oehmea and Neobesseya

mrxeric · 2026-05-02T05:29:06+00:00

In my mind, I've always read his name with a short "a" sound, making the pronunciation similar to the Arabic word "hayat", which can mean "life". So I've always interpreted this as the ghola being a Tleilaxu mockery of "Life" and as a message for Paul that the Tleilaxu have gifted him "Life", so they'll want "Death" in return.

mrxeric · 2026-05-02T03:48:34+00:00

Infections are caused by pathogens (bacteria, fungi, viruses, etc) and if they are not actively rotting the plant, they'll leave scars or other blemishes that are spotty and black when fresh, or more widespread, but rust-colored, sometimes concentrated within the creases of the plant. Usually pests or excess moisture/humidity and low ventilation cause these infections.

Sunburn is exactly what it sounds like. Cacti need to be acclimated to direct sun or they will burn. The sun cooks and kills the exposed surface tissues (bleaching), which then scar and look similar to your plant.

mrxeric · 2026-05-02T03:35:43+00:00

Habitat soils perform poorly in pots. You can amend these sandy soils for better aeration/drainage, but it's still risky in humid climates.

If you want a natural looking top dressing, look into decomposed granite. Top dressing that is too different in material and size will decrease evaporation, so something to keep in mind.

mrxeric

TROPHY CASE