Sempervivum, known as Houseleeks or Liveforever, are a genus of about 40 species of succulent plants of the Crassulaceae family which grow in rosettes. Another name used for some species is Hen and chicks....looks just like a crocheted blanket!
This photo of Cereus sp. spiralis is by Chantal Wagner [What a wonderfully odd plant! Unlike some it does not look like it is from an alien landscape; absolutely terrestrial but still odd. I like the shorter, uh, trunks? stems? but the combination of short with branched tall is really compelling — 13-07-13]