Hens and Chicks, sempervivums have their own forum.
"Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions.
The best known succulents are cacti (family: Cactaceae). Virtually all cacti are succulents, but not all succulents are cacti. There is a significant difference between succulents that evolved in Africa and those that evolved in the Americas, the New World plants called cacti all have spines.
To differentiate between these two basic types that seem so similar, but that are unrelated succulent plants, use of the terms, cactus or cacti, only should be used to describe succulents with spines.'' quoted from Wiki
But here's a pretty good description
http://www.associatedcontent.c...