Type of Flowers
Sempervivum:Sempervivum is a genus of about 40 species of flowering plants in the Crassulaceae family, known as houseleeks. Other common names include liveforever and hen and chicks. They are succulent perennials forming mats composed of tufted leaves in rosettes. In favourable conditions they spread rapidly via offsets, and several species are valued in cultivation as groundcover for dry, sunny spots.
Houseleeks occur from Morocco to Iran, through the mountains of Iberia, the Alps, Carpathians, Balkan mountains, Turkey, the Armenian mountains, in the northeastern part of the Sahara Desert, and the Caucasus. Their ability to store water in their thick leaves allows them to live on sunny rocks and stony places in the mountain, subalpine and alpine belts.
Like some other plants of Southern Europe, the ancestors of houseleeks are likely to have a subtropical origin. Morphologically, they are closely linked with the genera Jovibarba, Aeonium, Greenovia, Aichryson, and Monanthes, occurring mainly in Macaronesia (Azores, Canary Islands, Cape Verde, Madeira). Some botanists include some or all of these genera within a wider interpretation of Sempervivum, particularly Jovibarba.
The name Sempervivum has its origin in the Latin semper ("always") and vivus ("living"), because this perennial plant keeps its leaves in winter and is very resistant to difficult conditions of growth.The common name houseleek is believed to stem from the traditional practice of growing plants on the roofs of houses to ward off lightning strikes.The plant is not closely related to the true leek, which belongs to the onion family. Other common names reflect the plant's ancient association with Thor, the Norse god of thunder, and the Roman Jupiter. Hence names such as "Jupiter's beard" and the German Donnersbart ("thunder beard").
The genus Sempervivum is easy to recognize, but its species are often not easy to identify. Even one single clone can look very different under various growth conditions (modifications) or different times of the year. The members of this genus are very similar and closely linked to each other. As a consequence, many subspecies, varieties, and forms were described, without well-defined limits between them. As a second consequence, there is a high frequency of natural hybrids in this genus and the possibility of back-crossings of these. However, more or less 40 species can be individualized in the whole area of the genus, but there are many more local populations, without nomenclatural valour but sometimes with their own characters.
http://en.wikipedia.org/wiki/Sempervivum