Cleistocactus strausii
The cactus prefers free draining soils, strong sunlight, but not high temperatures — in fact it can withstand hard frosts down to -10 °C. In its natural habitat it receives plenty of water during the summer, but almost none over the winter. In cultivation, watering too much in winter often leads to root rot.
Astrophytum asterias
Sand Dollar Cactus has been grown as a houseplant since the 1840s, like other members of its genus and despite its rarity in the wild. It is readily propagated from seed, so most plants encountered in nurseries are seed grown. The popularity of this species among collectors and enthusiasts has ensured that a number of cultivars are available. One such cultivar is the 'Super Kabuto', a clonally propagated variety whose large trichomes congregate into dense spots, arranged in a striking pattern.