The flowers, in form of funnel, purple rosaceous or violet color, of 3.5 to 4,5cm of length and 3cm of diameter; the outer segments of perianthus are of two types: the exteriors like grudges brown green color and the others like pink petals; the internal segments of perianthus are of color purple or violet towards the end and clearer towards the base; the filaments are white, the yellow anthers, the white style that excels stamens slightly, and the lobes of stigma are of pale yellow color.

 
Mammillaria theresae cristata

The dry fruit and in nail form, of 10mm of length and 4mm of wide, remains contracted in the body, covered by a  white film. The seeds are black, of 0,5mm of length.

 
Mammillaria theresae flor blanca

It is a relatively abundant plant in its habitat, but not very easy to find in a nursery because the shortage of its seeds.

 
Mammillaria theresae  polytomic form

In culture forms of white flower, and cristate and polytomic forms are commercialized.

 
A curiosity: Mammillaria theresae double white flower.

The culture of Mammillaria theresae is difficult. The seeds are little and the seedling rots easily. For that reason, usually it is cultivated grafted on a stock of slow growth, which deforms its stems that tend to emit many sprouts. In culture, the atmosphere has to be dry and well ventilated, but it does not have to be exposed to the airflows. It is necessary to avoid watering in excess in summer and to keep it dry in winter. It requires a drained affluent substratum. The roots are very sensible to the excess of water.

   By Vicente Bueno, Illustrious Dr. Good of Cactus Center Club