ID please

[Eric Williams]

I have been asked to give this plant some TLC. Can any one ID It please. It is 16 inches high and 3 inches diameter, with small white flowers at apex. It seems to be over potted as it is extremely unstable when given to me. Thank you

[Tony R]

Looks like the white-flowered form of Mammillaria backebergiana (more usually has red-purple flowers)?

[David Neville]

Yes, I absolutely agree with Tony that this is the white flowered form of Mamm backebergiana. It naturally forms columnar stems, but the plant in the pix does look as if it may have suffered from lack of light at some stages of its life. Many plants with an upright or columnar tendency can be difficult because they become top heavy. If an elongated or columnar plant is repotted into a larger pot it can often take a while before the plant spreads its roots and becomes self supporting, so supports of some sort are frequently necessary....

[Eric Williams]

Thanks both for your expert advice. The owner does not have a green house, so the lack of good light seems to be the problem. When’re potted I will use a stake until it has settled. Cheers