Possible incorrect ID on echinopsis

[EvaLynn]

I bought this cactus a few weeks ago at a drought-tolerant-plant festival, and it had a tag identifying it as Echinopsis vallegrandensis.

I couldn't find that exact one online. The cactus with the most similar name that I found looked nothing like mine, although I did somehow make my way to Lobivia arachnacantha, which it resembles quite a bit.

The flower is about 1.75" across, while the cactus is about 1.5" across and about an inch tall.

Am I right about it being the Lobivia? Is there an explanation for the mix up anyone can think of beyond a huge WHOOPS?

Thanks for your help.

[EvaLynn]

To complicate things just a little, I went out to look at my collection and noticed that I bought a Lobivia arachnacantha from the same seller at a local nursery, and it really doesn't look like the cactus pictured above, so maybe that one isn't Lobivia arachnacantha. Here's the second cactus.

[Kamos]

The first one looks like possibly a Rebutia. Could you post a picture of the side view?

[EvaLynn]

Here's a side view of the first cactus.

[phil_SK]

They both look to be arachnacantha.

[greenknight]

I found Echinopsis vallegrandensis, it's a synonym of E. huotii - and it looks nothing like your plants. I agree, both are arachnacanthas.

[EvaLynn]

Sounds like we figured it out. I'll make a new tag -- thanks, everyone!

[eduart]

According to Rausch: Echinopsis arachnacantha var. vallegrandensis Rausch 1975 (and few other forms) = Lobivia arachnacantha Buining & Ritter 1956 var. densiseta Rausch 1968 / Echinopsis arachnacantha subsp. densiseta (Rausch) M.Lowry / Echinopsis arachnacantha var. densiseta Friedrich

[EvaLynn]

Yes!! Thanks, eduart -- that pulls it all together. I searched Lobivia arachnacantha var. densiseta online and found plants that look just like mine.