Discocactus placentiformis is a small globular cactus from Brazil that flowers on warm summer nights. While open, the flowers produce a delightful honeysuckle fragrance. In common with most (all?) other nocturnal cacti, Discocactus flowers last only a single night, and rapidly deteriorate and collapse into mush the next morning. If pollinated, the flowers are followed by white, balloon-like fruits containing a few black seeds.
This particular form of Discocactus placentiformis was formerly known as D. crystallophilus, because in the wild in Brazil it grows only on open ground covered with crystalline pieces of quartz. Like all members of its genus, D. placentiformis is uncommon and highly threatened in the wild by collection and development. Under glass, the plants aren't difficult, but appreciate milder winter temperatures and more generous summer watering than most of the other genera of compact cacti.
