Melocactus azureus v. ferreophilus Cactus They have some of the

They have some of the biggest spines of any Gymnocalycium

The caudex is brown and mostly smooth when young but in time becomes cracked and fissured

Produces big yellow flowers in summer

Tacitus bellus  AKA Graptopetalum bellum

The flowers are just a few millimeters wide but it flowers regularly during the warmer months unlike a lot of the showier Stapeliads that bloom once a year or so

Melocactus azureus v. ferreophilus Cactus They have some of theMelocactus azureus var. ferreophilus This is a nice cephallium forming species with green to blue green skin. It looks and grows like normal cactus several years but once it gets big enough the main plant stops growing but produces a large hairy inflorescence that continues to grow for the rest of the life of the plant. Eventually the inflorescence can be taller than the plant itself. This is more tropical than most succulents so it doesn't like cold