I was given this cactus many years ago. At that time I thought it was a barrel cactus because of its shape but it has gradually taken on a new look. Any idea what it is?
I think it is an Echinocactus grusonii that was grown in low light before you got it, and still shows some juvenile characteristics.
It looked very much like the one seen on the top of this Plantopedia page. It's been sitting behind a south facing window for as long as I can remember where it gets plenty of light. It receives a sip of water once a month along with a bit of fertilizer. The bottom portion does not look nearly as healthy as the top; it's somewhat dull and lighter in color. I may have stumbled upon the answer while looking for a sample picture for this post. According to the link above: The plant's location is partly shaded and the temperature is near that stated for part of the year, so perhaps that's the problem. What do you think?
When I saw this, I thought of my poor light-deprived thing that was thought to be Mammillaria. What would distinguish that from Echinocactus? Or distinguish yours from Eriosyce? This was my posting: Identification: - Eriosyce esmeraldana, or else what?
Probably yes, even if it looks as if it has grown in worse conditions earlier in its life. I have not had one in many years, but I grew mine outside (in summer) in as much direct sun I could provide. The body of an Echinocactus is divided in ribs (not on very young E. grusonii though) and flowers appear close to the apex (but mostly on big, old specimens). Mammillaria has smaller bodies with tubercles instead of ribs, and usually flower when still small, much smaller than Echinocactus. The flowers are small, 2 cm or so, are arranged in a circle at some distance from the apex, and come from the axils, the "valleys" between the tubercles (it is usually the areoles that bear flowers on cacti). The spines are smaller and weaker than those on Echinocactus. Eriosyce, or rather the subgenus Neoporteria, where esmeraldana belongs, are more difficult to describe, I learned to recognise them mostly by looking at a large number of pictures plus my own plants. They have ribs too, but they have notches between the areoles. The size is roughly the same as for Mammillaria, but the spines are stronger and often curved slightly upwards. Neoporteria flowers have a characteristic shape, are bigger than for the average Mammillaria, and the petals are often yellow and pink (picture). They appear on areoles close to the apex.
That was very helpful, @mandarin. Thanks. I can see dried up flower remains in the axils on my plant, and can see the difference in the spines, now that you mention it.
