Escobaria missouriensis x E. vivipara Intergrades?

[westfork]

In our search for native Escobaria populations here in the zone 4/5 Upper Midwest we came across an interesting situation where well established individuals of what appear to be both E. missouriensis and E. vivipara were growing near each other. Some individuals had the pink/red flowers of vivipara while others had yellow/white flowers which were likely missouriensis. We were well outside the native range of any other cactus species other than Opuntia. (Echinocereus viridiflorus and Pediocactus simpsonii would be many miles to the west.) I got the sighting from a reliable source but am unable to verify myself since these are on Lakota land.

Are there known instances of hybrid swarms between these two species?

Can they coexist so close together without hybridizing?

Has anyone tried crossing these two species and produced fertile offspring?

[FredBW]

I sort of study the Cold hardy cactus websight https://coldhardycactus.com/collections/all.
While I don't believe they have any missouriensis (they have 1 but sold out),they do have several vivipara. I think if it was possible to hybridize they would have done it. But that is just a guess.
They do have some hybridized Opuntia,which leads me to believe not so with Vivipara.
I also have a winter hardy cactus book by John Spain. He grew both of those for years with no mention of crossing as far as I know.

[westfork]

Thanks for the insight Fred. I tend to agree with you. Since their ranges overlap in so many places, if they did hybridize easily you would think there would be some mention of the intermediate forms. But I thought I would ask in case someone had experience with this.

[Tom in Tucson]

My guesses:

1) Since Escobaria missouriensis used to in a different genus (Neobesseya) they're likely too genetically different

2)They have different pollinators

3) Although Escobaria vivipara grows alongside many other species of Escobaria in Texas and Mexico, I've never seen any hybrids mentioned. As in 1), (genetically distinct).