Mediolobivia oculata, what's it really? Solved

[Terry S.]

I obtained this plant back in the early 1970s from Dennis Sargant on the Isle of Wight. He was importing Lau collected material at that time and this was bought from him as Mediolobivia oculata Lau 422. The problem is that Ralph's admirable database gives that number as an Echinopsis. So can anyone make sense of this, perhaps it had another number which changed a digit during transcription? It is a nice form but becomes useless if the associated collection data is completely mixed up.

[Paul D]

Lau 422a and 422b are both Mediolobivias- unfortunately both of these have been inappropriately spread as Lau 422 right from the 1930s (according to rebutia.sk). They are listed variously as steinmannii / applanata / cincinnata.
I don't have either plant in my collection to compare, I'm afraid.

[Ali Baba]

The picture of steinmanni ‘cincinnata’ in The cactus file handbook is a good match to your plant, which would match 422a, although the picture isn’t of that collection.

[ralphrmartin]

That plant's body looks like I would expect for occulata, being quite close to that of A. euanthema, which oculata is sometimes listed a variety or form of. However, oculata means eyed, and the flower does not have some change in colour in the throat which is what you would expect for a name like that. Maybe that's not a constant feature.

Some forms of A. euanthema do have a differently coloured throat (see the one I posted a couple of days back as my favourite plant, which is an extreme example).

The only numbers in my database for M. oculata are
RW378 oculata v. nov
RW595 oculata v.
None of the Lau numbers I have refer to oculata.

This page is very helpful (as it is for Rebutias, in the wide sense, in general)
http://www.rebutia.sk/select/names/oculata_s.htm

I suspect that the plant the gets called A. euanthema v. tilcarensis and related names these days is perhaps what was meant by oculata:

E.g.

MN163

WR700

[Phil_SK]

Even though it was first published in 1935, the original description includes a colour photo:
https://www.cactuspro.com/lecture/Werde ... 56.en.html
The text is on the following page.
While I was hunting around for this, I came across a formal proposal in Taxon to reject the name in favour of euanthema.

hjertseuanth.JPG (108.98 KiB) Viewed 1477 times

It didn't succeed, so euanthema isn't valid at species level - oculata is.
I don't think your plant is that, though.

[ralphrmartin]

Thanks for the pointer to the picture Phil. I think (well, hope, anyway) the flower in the original description is consistent with those on the plants in my photos.

[Terry S.]

Thank you for these helpful replies. My basic confusion is that Lau 422 is listed as a Parodia (not Echinopsis as I said initially) in the Field Number Data Base. However our National Collection holder has been able to tell us that Lau 422 is usually regarded as Mediolobivia (or whatever genus) steinmannii. Any identification of this material was probably provisional and carried out by Lau or Sargent, so I am not particularly concerned about what microname was put on it. I will now be happy to distribute this clone as Aylostera steinmannii Lau 422 using current nomenclature. The plant is undergoing a two stage demolition because the bottom parts of the stems are now rather brown after 45 years!

[Paul D]

Thank you for these helpful replies. My basic confusion is that Lau 422 is listed as a Parodia (not Echinopsis as I said initially) in the Field Number Data Base. However our National Collection holder has been able to tell us that Lau 422 is usually regarded as Mediolobivia (or whatever genus) steinmannii. Any identification of this material was probably provisional and carried out by Lau or Sargent, so I am not particularly concerned about what microname was put on it. I will now be happy to distribute this clone as Aylostera steinmannii Lau 422 using current nomenclature. The plant is undergoing a two stage demolition because the bottom parts of the stems are now rather brown after 45 years!

Not 422 though, Terry, but 422a. Lau collected three different plants, 422, 422a and 422b. As far as I can tell 422b has been "lost", 422 is a Parodia, and 422a is likely to be your plant.
The habit that collectors have of numbering different plants with the same number but putting a letter after them to distinguish them has long been a source of annoyance for me, particularly when some collectors not only do that, but will even use a small "a" for one plant and a captial "A" for a different plant. No wonder that confusion arises.
I agree with Ralph that it is probably what was called Lobivia euanthema, but oculata (as Aylostera oculata (Werderm.) Mosti & Papini, comb. nov.) was resurrected by them in their 2011 review after molecular studies.

[Terry S.]

Thanks again. Many collectors/observers use the a,b,c system to denote different species growing at the same locality - this is what Des Cole did when Lithops finds grew in mixed populations.

[Phil_SK]

oculata (as Aylostera oculata (Werderm.) Mosti & Papini, comb. nov.) was resurrected by them in their 2011 review after molecular studies.

I came across that name, too, yesterday, but it's nom. inval. as they listed the basionym wrongly.