Until 2 years ago, there were considered to be (at least) two distinct forms of Agave titanota: a glaucous bluish white plant mostly lacking a pale midstripe on the leaves, and a green form with a midstripe.

The green plant was described as a separate species in 2019 (Agave oteroi) but a lot of people either haven't heard of the change or don't accept it, so there's confusion about which species epithet should be used for which cultivar, among the many named cultivars.

This thread is an attempt to systematically resolve that confusion. Please speak up if you have comments or disagree, or if you would like to add other plants to the list.

First, here are the 2 species in question, to get acquainted:




This is the only cultivar we have as titanota, the blue-white plant. I have included a link to a site with a decent pic.

Agave 'X-Rays'
https://www.plantdelights.com/...

These remaining entries are oteroi, the green plant.



Sierra Mixteca Agave (Agave oteroi 'Banana Peel')
https://www.plantdelights.com/...

Sierra Mixteca Agave (Agave oteroi 'Filigree')
https://www.smgrowers.com/prod...

Sierra Mixteca Agave (Agave oteroi 'Filigree Devil')
https://www.smgrowers.com/prod...

Sierra Mixteca Agave (Agave oteroi 'Genryu Kifukurin')
https://www.plantdelights.com/...

Sierra Mixteca Agave (Agave oteroi 'Kyoto')
https://www.smgrowers.com/prod...



Sierra Mixteca Agave (Agave oteroi 'Mean Streak')
https://www.plantdelights.com/...

Sierra Mixteca Agave (Agave oteroi Snaggle Tooth)
https://www.plantdelights.com/...

Sierra Mixteca Agave (Agave oteroi 'Solar Eclipse')
https://www.smgrowers.com/prod...

Sierra Mixteca Agave (Agave oteroi 'Sunburst')
https://www.plantdelights.com/...

They should all be searchable as titanota, thus accessible to people familiar with the old name for the green plant.

Greg Starr would call the 2nd of the first two titanota photos not titanota but a blue oteroi hybrid probably with titanota and mixed in, mainly because the corneous edges are way too developed to fit within the A. titanota variation observed within the A. titanota population at the type locality (Rancho Tambor) - aside from the obvious differences in leaf size and shape. Though the people who collected seed and brought selections like this to market are cagey about about where they did collect, all we know is that it is highly unlikely that they made it to Rancho Tambor - which is the type locality - and which is difficult to get to.

Similarly he would call everything with a midstripe like the one cultivar that PDN brought to market a hybrid as well, in all likelihood with significant kerchovei or oteroi mixed in.

I think GS may be what you'd call an Agave titanota purist, but if you check the actual official description of Agave titanota none of these very toothy cool looking plants actually fit, so maybe he has a point from a taxonomical point of view. On top of that there is a much easier to access population of what is probably best described as agave oteroi merging into a hybrid swarm with kerchovei and some titanota genes. There is kerchovei there, but it is a significant ways away from where titanota occurs. Many of the varieties you see with some kind of titanota label in the trade can be seen growing in the wild there.

There are numerous posts on this subject on Agaveville.org for those willing to dive in...

Do you think our entry for the plant below (X Rays) should be under Agave (alone, no species named) in the database, instead? Would that be more accurate? I'm trying to make the location best fit the plant.

https://www.plantdelights.com/...

Do you think Angelo's small white plant pic (#2 above) should be moved to Agave?

Well PDN is certainly not going to change their name that we can be sure of. So, if you want people to find the PDN plant you'd probably should keep it under titanota. Also I was telling you what I think GS would say, and while I think I am confident about that given that I have heard/read him talk/write about this several times, I cannot be completely sure. Maybe stick a note with the plant that based on midstripe and development of the corneous margins this is likely a hybrid of titanota...

As to Angelo's plant: Imagine if you saw the first three photos for the first time without any of the previous naming stuff. If you were told that the first pic was what Agave titanota looks like and the third pic is Agave oteroi. What would you think the 2nd plant was?

A. Agave titanota
B. Agave oteroi
C. A combination of the first and third picture - thus a hybrid, shape and size from oteroi, coloring from titanota.

Now and this is why I have always had issues with all these misnamed titanotas, the 2nd picture looks nothing like the first picture, except for the coloring. However, if you would go by the just the coloring to call it titanota then there are a whole other slew of grey-white-alabaster Agaves that you'd start calling titanota... The argument people who were bringing these plants to market made is that they were growing seed that was collected from Agave titanota, except that in all likelihood they weren't... The original argument has always been these green plants are titanota because we are growing titanota seed and they appeared among the seedlings, but very few of the non green seedlings actually looked a lot like what Agave titanota looks like at Rancho Tambor. Making a number of people doubt that it was truly titanota seed from Rancho Tambor.

But to go back to my multiple choice question: I'd say either B or C, certainly not A. I think my answer would be C, though if you'd say B, I could go there, but I'd probably point to the description of Agave oteroi and to show that it was described as a green plant not a blue grey plant.

I will move those two presumed hybrids to the genus and drop the species name from them, then. I will endeavor to annotate the entry for the PDN release with a comment reflecting your thoughts about its species origins.

All the cultivars that were at one point called titanota should be searchable under titanota, regardless of their address in the database. At least that's what I've been trying to make possible. A couple mighta slipped through.

@BlueOddish that white agave picture of yours (#2 at top) is going to the genus entry, unless you disagree.

Thank you for your input here, Thijs. I was hoping you would share your thoughts, and that's partly why I started this thread.

You are welcome. I should be clear: I have not been in habitat, but I have followed the discussion and the efforts to sort the issue with these plants out closely and I have heard people who have been in habitat speak and seen their pictures. So while based on that I have an opinion I would not ever want to claim expertise.

What seems so weird is that it almost seems like that peope think the plant is less cool and awesome because it isn't Agave titanota, which is ridiculous.

I have Agave titanota and while it is a great plant because of its almost white color, other than that it is much less interesting looking than Agave oteroi and all the hybrids/cultivars with oteroi in it.