Mammillaria senilis

This old classic is one of the most thought after Mammillarias. The plants are large, snow-white with dense spines, decorated with long pale-yellow tipped hooks. Showy flowers are among the largest in genus, the unusual shape strongly suggesting hummingbirds dependence for pollination.
Successful flowering of Mammillaria senilis is surrounded by some sort of mystery, but apparently there is no big secret there. Flowering buds are started fairly early by this species, as early as late August or early September. The plants need plenty of light in months prior, and in the fall to successfully develop them. The plants of 6cm diameter are ready to bloom, and some time in November tiny bright red buds could me spotted deep  in axiles. Early spring is when the flowers fully develop.