Austrocylindropuntia shaferi

Two years old from seeds plant flowering in by backyard. This is a very vigorous plant, and at that young age produced unexpected flowers. The first flowers are small, but the color is striking.
The same plant 2 years back: http://cactusaficionado.blogspot.com/2012/04/austrocylindropuntia-shaferi.html

Coryphantha erecta

Coryphantha erecta was described about 150 years ago, but generally neglected by cactus collectors. It is a somewhat trivial looking plant, with very pretty summer blooms.

Copiapoa laui

The smallest of all Copiapoas, with tiny button-head stems, is underground plant in the nature. Stems are usually flat to the ground, and really hard to find when not in bloom. In culture they form small multi-headed clumps.

Mammillaria grahamii

Mammillaria grahamii is a common plant of southern and central Arizona. There are several different forms of this plant found throughout the state. This form with tight white radial spines covering the steam and striped flower comes from Organ Pipe Cactus National Park.