Ubelmannia pectinifera

Ubelmannias are native to  Brasil where they grow in rocky arid habitats, surrounded by grasslands and semi-dry forests. Older habitat plants often develop white stem color, similar to many Copiapoas, and like Copiapoas, cultivated Ubelmannias very rarely do that.

Mammillaria perezdelarosae andersoniana

6 months old seedlings.

Eriocactus (Parodia) warasii

Eriocactus is a small group of species now listed under Parodia with distinct flower, almost identical among all species in the group. All the Eriocacti are by far the largest in the Parodia genus.

Copiapoa hypogea

Copiapoa hypogea along with C. humilis are the most commonly seen Copiapoas in collections. They flower easily, with characteristic for the genus yellow flowers.
It would be difficult to make an impression of the whole plant from my picture, but that was not the intention either ))

Ariocarpus fissuratus

Summer is almost over and Ariocarpus flowering season has started. A. fissurratus stem is grey and textured like rock, blending to the environment. The fleshy root is much larger then the stem above the ground, and the plant grows almost flat to it's surface.

Grusonia parishii

This is the first Grusonia flower in my greenhouse. Fully open flower is flat like a pancake, but soon after I has photographed it I noticed that the flower started to close, curling the petals back inside. This ephemeral shape seemed much more elegant to me, so I brought my camera back for it.

Matucana madisonorum

This is a more common Matucana, usually known as a naked ball with eventual spine or two. When grown on strong light, they actually develop long brown spines, somewhat twisted.