Notocactus mammulosus

Genus Notocactus is currently merged with older genus Parodia and it probably makes sense, but from the collector perspective it is usually not hard to tell one from another, so I'm using the old name here.
Notocactus mammulosus is somewhat neglected by collectors species, by no good reason. It is easy to grow plant, forming flattened disk-like stem with distinct white areoles and dark stubby central spine. Large silky flowers come only once per season, but they are very noticeable and usually abundant.