Houseleek
Encyclopedia
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 (and also for some plants in other related genera) is Hen and chicks
.
to Iran
, through the mountains of Iberia
, the Alps
, Carpathians
, Balkan mountains
, Turkey
, the Armenia
n 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
, their ancestors have likely 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
.
Semper ("always") and vivus ("living"). Sempervivum are called "always living" because this perennial plant keeps its leaves in winter and is very resistant to difficult conditions of growth.
but monocarpic
rosettes
. Each rosette propagates asexually
by lateral rosettes (offsets
, "hen and chicks
"), by splitting of the rosette (only Jovibarba heuffelii
) or sexually
by tiny seeds.
Typically, each plant grows for several years before flowering. Their hermaphrodite flowers have first a male stage. Then the stamen
s curve themselves and spread away from the carpels at the center of the flower, so self-pollination
is rather difficult. The colour of the flowers is reddish, yellowish, pinkish, or - seldom - whitish. In Sempervivum, the flowers are actinomorphic (like a star) and have more than six petals, while in Jovibarba
, the flowers are campanulate (bell-shaped) and are pale green-yellow with six petal
s. After flowering, the plant dies, usually leaving many offsets it has produced during its life.
) 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 form
s were described, without well-defined limits between them. As a second consequence, there are 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 population
s, without nomenclatural valour but with sometimes their own characters.
In the Alps, for example, the most distributed species are Sempervivum tectorum (Common Houseleek, sometimes called Sempervivum alpinum), Sempervivum montanum (Mountain Houseleek) and Sempervivum arachnoideum (Cobwebbed Houseleek), each one with several subspecies. More local are the yellow-flowered S. wulfenii and S. grandiflorum, and the beautiful Limestone Houseleek (S. calcareum). More rare are S. dolomiticum and mainly S. pittonii. S. pittonii is a small yellow-flowered jewel which grows only on two mountains slopes near Kraubath in the Mur valley in Austria and is very threatened.
On roofs or old walls S. tectorum can be found, more or less wild, very far out of its natural area. It is a very old medicinal and witch-plant. Some superstitious
people believe that this plant is able to protect a house from lightning
.
plants. They require only moderate water and some protection from extreme exposure to the sun.
Sempervivums grow very well in dry conditions. Despite this if Sempervivums are grown in normal flower beds among other cultivated plants there can be a problem. If the flower beds are not particularly dry other plants may grow more strongly than the Sempervivums and overshadow them. Other plants may need to be removed, cut back or tied out of the way.
"Semp-lovers" are numerous and often have many different cultivar
s in their collections. Sempervivums are very variable plants and hence hundreds, maybe thousands of cultivars were created, but a lot of them are not much different from each other. The main interest of these cultivars are not their flowers, but form and colour of the rosette-leaves. The most colourful time is generally from March till June.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of about 40 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of succulent plants of the Crassulaceae
Crassulaceae
Crassulaceae, or the orpine family, are a family of dicotyledons. They store water in their succulent leaves. They are found worldwide, but mostly occur in the Northern Hemisphere and southern Africa, typically in dry and/or cold areas where water may be scarce...
family which grow in rosettes
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
. Another name used for some species (and also for some plants in other related genera) is Hen and chicks
Hen and chicks
thumb|right|240px| Jovibarba globifera showing larger mother plants and smaller, globe-shaped [[offsets]] .thumb|right|240px| Sempervivum tectorum...
.
Habitat
They occur from MoroccoMorocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
to Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
, through the mountains of Iberia
Iberian Peninsula
The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...
, the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
, Carpathians
Carpathian Mountains
The Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...
, Balkan mountains
Balkan Mountains
The Balkan mountain range is a mountain range in the eastern part of the Balkan Peninsula. The Balkan range runs 560 km from the Vrashka Chuka Peak on the border between Bulgaria and eastern Serbia eastward through central Bulgaria to Cape Emine on the Black Sea...
, Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
, the Armenia
Armenia
Armenia , officially the Republic of Armenia , is a landlocked mountainous country in the Caucasus region of Eurasia...
n mountains, in the northeastern part of the Sahara Desert, and the Caucasus
Caucasus
The Caucasus, also Caucas or Caucasia , is a geopolitical region at the border of Europe and Asia, and situated between the Black and the Caspian sea...
. 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.
Subtropical origin
Southern Europe
The term Southern Europe, at its most general definition, is used to mean "all countries in the south of Europe". However, the concept, at different times, has had different meanings, providing additional political, linguistic and cultural context to the definition in addition to the typical...
, their ancestors have likely a subtropical origin. Morphologically, they are closely linked with the genera Jovibarba
Jovibarba
Jovibarba is a small genus of three species of succulents in the family Crassulaceae, endemic to mountainous regions in the southeastern quadrant of Europe. The genus is closely related to Sempervivum. Some taxonomists classify it as a subgenus of Sempervivum...
, Aeonium
Aeonium
Aeonium is a genus of about 35 species of succulent, subtropical plants of the family Crassulaceae.The name comes from the ancient Greek "aionos" ....
, Greenovia, Aichryson
Aichryson
Aichryson is a genus of about 15 species of succulent, subtropical plants, mostly native to the Canary Islands, with a few in the Azores, Madeira and Morocco, and one in Portugal.The species of Aichryson are not frost-resistant...
, and Monanthes
Monanthes
Monanthes is a genus of small, succulent, subtropical plants of the Crassulaceae family. The about ten species are mostly endemic to the Canary Islands and Salvage Islands, with some found on Madeira. Its center of diversity is Tenerife, with seven species occurring on this island. On...
, occurring mainly in Macaronesia
Macaronesia
Macaronesia is a modern collective name for several groups of islands in the North Atlantic Ocean near Europe and North Africa belonging to three countries: Portugal, Spain, and Cape Verde...
(Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
, Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
, Cape Verde
Cape Verde
The Republic of Cape Verde is an island country, spanning an archipelago of 10 islands located in the central Atlantic Ocean, 570 kilometres off the coast of Western Africa...
, Madeira
Madeira
Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...
). Some botanists include some or all of these genera within a wider interpretation of Sempervivum, particularly Jovibarba
Jovibarba
Jovibarba is a small genus of three species of succulents in the family Crassulaceae, endemic to mountainous regions in the southeastern quadrant of Europe. The genus is closely related to Sempervivum. Some taxonomists classify it as a subgenus of Sempervivum...
.
Origin of name
The name "Sempervivum" has its origin in the LatinLatin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
Semper ("always") and vivus ("living"). Sempervivum are called "always living" because this perennial plant keeps its leaves in winter and is very resistant to difficult conditions of growth.
Growth and reproduction
Houseleeks grow as tufts of perennialPerennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
but monocarpic
Monocarpic
Monocarpic plants are those that flower, set seeds and then die. Other terms with the same meaning are hapaxanth and semelparous. The term was first used by Alphonse de Candolle....
rosettes
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
. Each rosette propagates asexually
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
by lateral rosettes (offsets
Offsets
In botany and horticulture Offset is a term used to describe a small virtually complete daughter plant that has been naturally asexually produced on the mother plant. They are clones , meaning that they are genetically identical to the mother plant. In the plant nursery business and gardens they...
, "hen and chicks
Hen and chicks
thumb|right|240px| Jovibarba globifera showing larger mother plants and smaller, globe-shaped [[offsets]] .thumb|right|240px| Sempervivum tectorum...
"), by splitting of the rosette (only Jovibarba heuffelii
Jovibarba
Jovibarba is a small genus of three species of succulents in the family Crassulaceae, endemic to mountainous regions in the southeastern quadrant of Europe. The genus is closely related to Sempervivum. Some taxonomists classify it as a subgenus of Sempervivum...
) or sexually
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
by tiny seeds.
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s curve themselves and spread away from the carpels at the center of the flower, so self-pollination
Self-pollination
Self-pollination is a form of pollination that can occur when a flower has both stamen and a carpel in which the cultivar or species is self fertile and the stamens and the sticky stigma of the carpel contact each other in order to accomplish pollination...
is rather difficult. The colour of the flowers is reddish, yellowish, pinkish, or - seldom - whitish. In Sempervivum, the flowers are actinomorphic (like a star) and have more than six petals, while in Jovibarba
Jovibarba
Jovibarba is a small genus of three species of succulents in the family Crassulaceae, endemic to mountainous regions in the southeastern quadrant of Europe. The genus is closely related to Sempervivum. Some taxonomists classify it as a subgenus of Sempervivum...
, the flowers are campanulate (bell-shaped) and are pale green-yellow with six petal
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
s. After flowering, the plant dies, usually leaving many offsets it has produced during its life.
Identification
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 (modificationsModifications (genetics)
In opposition to mutations, modifications are included in the band width of the genome of an individual creature. Modifications are dependent on the plentifulness of the substrate, light, warmths, stress, training, and so on....
) 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
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, varieties
Variety (biology)
In botanical nomenclature, variety is a taxonomic rank below that of species: as such, it gets a three-part infraspecific name....
, and form
Form (botany)
In botanical nomenclature, a form is one of the "secondary" taxonomic ranks, below that of variety, which in turn is below that of species; it is an infraspecific taxon...
s were described, without well-defined limits between them. As a second consequence, there are 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 population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
s, without nomenclatural valour but with sometimes their own characters.
On roofs or old walls S. tectorum can be found, more or less wild, very far out of its natural area. It is a very old medicinal and witch-plant. Some superstitious
Superstition
Superstition is a belief in supernatural causality: that one event leads to the cause of another without any process in the physical world linking the two events....
people believe that this plant is able to protect a house from lightning
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
.
Garden plants
Although their subtropical cousins are very frost-sensitive, Sempervivums are among the most frost-resistant succulents, making them popular gardenGarden
A garden is a planned space, usually outdoors, set aside for the display, cultivation, and enjoyment of plants and other forms of nature. The garden can incorporate both natural and man-made materials. The most common form today is known as a residential garden, but the term garden has...
plants. They require only moderate water and some protection from extreme exposure to the sun.
Sempervivums grow very well in dry conditions. Despite this if Sempervivums are grown in normal flower beds among other cultivated plants there can be a problem. If the flower beds are not particularly dry other plants may grow more strongly than the Sempervivums and overshadow them. Other plants may need to be removed, cut back or tied out of the way.
"Semp-lovers" are numerous and often have many different cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s in their collections. Sempervivums are very variable plants and hence hundreds, maybe thousands of cultivars were created, but a lot of them are not much different from each other. The main interest of these cultivars are not their flowers, but form and colour of the rosette-leaves. The most colourful time is generally from March till June.
External links
- http://sempervivophilia.stalikez.info/ from Gérard Dumont (in French and in English; some pages in German and Spanish. Photos of the species in their natural habitats)
- http://www.sempervivum.ru/ (mostly in Russian)
- http://www.kallimagarden.com/ekatalog.php?menuID=enk_semp&page=eabc_2.php&dbID=semp_druhy&pismeno=A&seria=0 (in Slovak and in English)
- Sempervivum Database
- Drought Smart Plants