I was once told that to identify the cacti on Scrivener Hill I should wait until they flowered. Local residents are planting O. ficus-indica but I don't know how this got here. By the way spelling is O. elatior.
Mike, Harley Baker one of our weed ecologists, got back to me and said, from the photo I would say I haven’t seen this one around before. I think O.eliator looks to be a likely suspect but from what I can see online most photos of it show O.eliator as having fewer more spaced out areoles than the photo on CNM. This would be a good one to take a sample of to the National Herbarium for an accurate ID" Are you able to take one of the cactus segments and drop off to Dave Albrecht at the Herbarium? Can you leave the plant alive until ID has been confirmed, in case Dave needs a flower. No worriesif getting to the Her barium is a hassle, Harley has offered to do it if need be.
I have found another plant nearby that can spare a segment. Blades are about 25 cm with 4 cm spines. I have added photo to iNaturalist for their cactus experts. Some nearby O. ficus-indica that has been ripped out has 1 cm spines on fresh growth.
iNaturalist has suggested Opuntia elata or "Could be the spiny form of Opuntia ficus-indica. See this link: https://www.opuntiads.com/opuntia-ficus-indica/". The link has similar images of "Opuntia ficus-indica, reverting to O. streptacantha look" so that might be in the genes.