With young plants from large nurseries that you can buy in flower shops or garden centres, it is sometimes difficult to determine the species with certainty: The body and spination are often not yet typically developed and for a sure identification you usually need the flower. In addition, they can ...

cactuspip wrote: ↑Tue Aug 16, 2022 12:51 pm It means it comes from Mendoza province.

Gymnocalycium mendozaense is named after the military station Gabino Mendoza in the Paraguayan province Boqueron.

Dear Ralph,
you are right, Notocactus acutus is classified as a synonym of P. oxycostata. JanD's plant is still young and "well fed", the angular ribs will certainly become more obvious later.
Detlev

The first picture definitely does not show a Gymnocalycium, but a plant from the relationship of Parodia ottonis (Notoactus ottonis). Parodia ottonis sensu lato is a very variable species and many forms have been described as separate species. The plant shown corresponds to Parodia oxycostata (but w...

There is also this colour wheel. Though it has been blown up from a tiny pic, and I don't think is a reliable guide to the colours! Imagine it brighter.

This already looks good, but here is a scan from the printed copy.

I found an online version here https://dtpstudio.de/atlas/farbsysteme/ ... bs00_3.htm

Good tip, I didn't know that webpage yet.

Ritter used the colour chart of E. Biesalski: "Pflanzenfarben-Atlas", which was published in 1957. The colour chart is based on the German standard DIN 6164. Unfortunately it is no longer available. I got my copy many years ago from an old cactus friend. Once it was offered by Schwarz, but...

What I see in the Jura's pictures is that the spines are pale yellow and significantly thicker than those of G. baldianum.
Otherwise, of course, Mat is right: many Gymnocalycium look very similar, especially when young without flowers.
Mat`s plant may be a G. baldianum.

Although the spines are quite short, it will be a form of Gymnocalycium monvillei. A flower could confirm this. But a hybrid is possible, too.

Gymnocalycium pungens is an old name of Czech origin. It was used as G. schickendantzii var . pungens, but published as species name in 1962 (but the description is not valid). G. pungens is only a form of G. schickendantzii with straight spines (the spines of G . schickendantzii are often hooked or...