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Echinofossulocactus for id

Posted: Wed Mar 31, 2021 3:47 pm
by ralphrmartin
Most Echinofossulocacti have purple flowers. This one has white flowers, but also looks very different to my plant of E. albatus. Can anyone suggest a name for it? Its thin, dark central spines seem quite distinctive.
IMG_20210331_122359.jpg

Re: Echinofossulocactus for id

Posted: Thu Apr 01, 2021 10:24 pm
by AndrewB
It looks somewhat similar to some online photos of multicostatus or lloydii.

Re: Echinofossulocactus for id

Posted: Fri Apr 02, 2021 6:47 pm
by ralphrmartin
Thanks Andrew.

It's not multicostatus, I'm pretty sure - that has many more ribs, as the name suggests - and somewhat flattened central spines.

There are lots of hybrids and dodgy names in this genus, I am afraid. I guess my plant may be a hybrid.

Re: Echinofossulocactus for id

Posted: Fri Apr 02, 2021 6:55 pm
by Phil_SK

Re: Echinofossulocactus for id

Posted: Fri Apr 02, 2021 8:58 pm
by Stuart
Taylor, when he worked at Kew, lumped all Stenocacti into Hastatus with the exception of Coptonogonus , Albatus and Zacatecasensis if I remember correctly. From those I've seen in habitat, they do all look like the same species. That's the only time I've agreed with him!

Stuart

Re: Echinofossulocactus for id

Posted: Sun Apr 04, 2021 1:16 pm
by ralphrmartin
Phil_SK wrote: Fri Apr 02, 2021 6:55 pm A key.
Phil, were you saying a key is needed? Or did you forget to include a link to a key?

Thanks!

Re: Echinofossulocactus for id

Posted: Sun Apr 04, 2021 1:21 pm
by Aiko
The text IS the link, Ralph.

Re: Echinofossulocactus for id

Posted: Sun Apr 04, 2021 3:58 pm
by ralphrmartin
Thanks Aiko. It shows up just the same colour as the other text, at least on my computer / browser, so it's not obvious it's a link.

Apologies, Phil.

Re: Echinofossulocactus for id

Posted: Sun Apr 04, 2021 4:28 pm
by ralphrmartin
So let's try the key
1 => Inner perianth segments are white with pinkish midstripe => 2
2 => Ribs over 30 => 3
3 => Ribs 30+ but not as many as 50, epidermis dark green, flowers with pinkish / purplish tints

That makes it E. crispatus.

Going to page 39 after the key, it discusses plants in the E. crispatus complex. Most of those are described as having white or yellow central spines. Those on my plants are much darker. That leaves the following in the E. crispatus complex:
crispatus (undefined spine colour): no, this has purple-violet flowers
lamellosus (spines white tipped brown) no, this has carmine flowers
lancifer (spines white tipped brown) no, this has only 4 radial spines
lexarzai (spines whitish with dark tips) seems to be the best match:
it has 40-50 ribs; my plant has in the high 30s,
4 central spines,
8-10 white radial spines,
flowers 30mm long; mine are a bit shorter)
flower white with purplish-red midstripes
obvallatus (undefined spine colour) : no, this has only 20 ribs

So, despite Nigel Taylor, I'm going to call it E. lexarzai. I'd never even heard of that.

Thanks for the reference, Phil.

Re: Echinofossulocactus for id

Posted: Sun Apr 04, 2021 4:34 pm
by Phil_SK
There is a photo with the first description: https://www.biodiversitylibrary.org/ite ... 9/mode/1up