Discocactus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of tropical

Tropics

The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately  N and the Tropic of Capricorn in the southern hemisphere at  S; these latitudes correspond to the axial tilt of the Earth...

 cactus

Cactus

A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...

. The name comes from the ancient Greek "diskos" (=disc) because of its shape. Discocactus plants are endemic to southern Brazil, eastern Bolivia, and northern Paraguay. These species are in the risk of extinction in the wild.

The plants have a slightly flattened spherical shape. Areole

Areole

Areoles are an important diagnostic feature of cacti, and identify them as a family distinct from other succulent plants. The areoles on cacti are clearly visible; they generally appear as small light- to dark-colored bumps, out of which grow clusters of spines...

s bear sharp spines. At the apex of the adult plants, appeared a woolish cephalium

Cephalium

Cephalium is a, frequently brightly coloured, structure of wool and bristle at the growing tip of certain cacti. It is most commonly found on cacti of the genus Melocactus and can take a number of colours, forms and shapes....

white ot z little bit yellow or grey.