I had been informed that propagation from individual areoles of Mammillaria plumosa was possible. When I broke my clump up and tried to root the cuttings, some developed roots arising from an individual areole but the whole cutting was not taking root. I broke off a number of rooted areoles and planted them. They survived for over a year without growing, then most withered away and died. Except for these 4. You can see the old brown feathery spines of the original areole and the development of a growing tip, especially on the lower right plant.

Not that I needed them to survive as the other cuttings from the clump had a great strike rate and I have more than 2 dozen new plants.