Lithops
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Lithops is a genus of succulent plants from the family of aizoaceae (Aizoaceae) and belongs to the subfamily Ruschioideae . The botanical name of the genus is derived from the Greek nouns "λίθος" (lithos) for "stone" and "ὅψις" (opsis) for "appearance" and refers to the similarity of the plants with the stones between which they normally grow. In German they and other such adapted succulent plants are also called " living stones ". The species of the genus Lithops are common in southern Africa in Botswana, Namibia and South Africa.
Special botanical names
To describe the genus Lithops and their species, botanists introduced some special names. The head is the overgrown pair of leaves that form the plant body. The rear division between the two sheets is called the gap . This divides the head into two praises . The end face is the top blade face of a head. On the end face there are translucent or semi-translucent areas called windows and opaque areas called islands . If there are many or large islands, the windows are reduced to channels . The inner and outer opaque areas on the end face that enclose windows and channels are called rims . In the windows or channels of many types, red dots, dashes, hooks or lines appear, which are summarized under the heading rubrication .
description
Adult plants are divided into two mostly unequal leaves (praise) by a gap. These praises are shaped like a top or almost cylindrically grown together. They have an almost conical shape, which keeps the surface area small compared to the volume, so that evaporation remains minimal. When fully grown, the lobes reach a diameter of about 2 to 5 cm and a height of about 3 cm.
Light penetrates the plant through so-called windows through the upper end of the lobes. Lithops tolerate direct sunlight and a climate that is characterized by low precipitation and frost-free conditions.
The yellow or white flowers appear after the rainy season at the end of the main growing season (September to November) from the gap between the lobes.
The plants develop a pair of new leaves every year. During the dry season , the old pair of leaves surrounds the new one and also serves as a water dispenser. If the plant is old enough, two pairs of praise can arise from one specimen ( vegetative reproduction ). In the literature plants are mentioned that had up to 200 heads; these had to be several decades old. The older the plant gets, the more difficult it is to keep.
Lithops have tap roots , so they can reach water even at greater depths.
Lithops are an example of mimesis in plants. Since they are similar in shape and color to the stones in their environment, they are difficult to find for herbivorous animals during the rest period because they are well camouflaged . In the vegetation phase, only the surface of the plants can usually be seen. This also protects the plants from extremely strong sunlight.
Systematics and distribution
The distribution area of the genus Lithops extends in Namibia from Kaokoland to Warmbad and in South Africa includes the provinces of North Cape , Western Cape , Eastern Cape , Free State , Northwest , Gauteng , and Limpopo . Few populations of Lithops lesliei have been found in southeastern Botswana .
According to Desmond Thorne Cole , the genus consists of:
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Botanical history
On September 14, 1811, William John Burchell , who was near Prieska in what is now the South African province of North Cape , noted :
“Picking up some of the stony ground, which was supposedly an oddly shaped pebble, turned out to be a plant that was another species in the extensive Mesembryanthemum clan, but which was extremely similar in color and appearance to the stones between which it grew. "
Adrian Hardy Haworth described this new species for the first time in 1821, based on a drawing by Burchell, which Burchell made almost a year after it was found and on which the plant was called Mesembryanthemum turbiniforme .
It was not until almost a century later that Nicholas Edward Brown established the genus Lithops and, in addition to Mesembryanthemum turbiniforme, assigned the species Mesembryanthemum pseudotruncatellum (described in 1908), which he or Alwin Berger , Rudolf Marloth , Kurt Dinter and Gustav Schwantes had described since the beginning of the 20th century. , Mesembryanthemum opticum (1910), Mesembryanthemum lesliei (1912), Mesembryanthemum fulviceps (1914), Mesembryanthemum karasmontanum (1920), Mesembryanthemum marmoratum (1920) and the new species Lithops bella zu. The also known Mesembryanthemum hookeri (discovered in 1874) and Mesembryanthemum locale (described in 1920), however, he left in the genus Mesembryanthemum .
Danger
Appendix I of the Washington Convention on Endangered Species does not contain any species of the genus Lithops . In the Red List of Threatened Species of IUCN seven species, however, are listed with different threat status. Three species, Lithops francisci , Lithops hermetica and Lithops werneri , are considered threatened (" Vulnerable (VU) "). Lithops optica is at low risk (" Near Threatened (NT) "). When not at risk ( " Least Concern (LC) ") are Lithops fulviceps , Lithops ruschiorum and Lithops vallis-mariae classified.
proof
literature
- Desmond T. Cole, Naureen A. Cole: Lithops: Flowering Stones . Cactus & Co. 2005, ISBN 88-900511-7-5 .
- DT Cole, NA Cole: Lithops . In: Heidrun EK Hartmann: Illustrated Handbook of Succulent Plants: Aizoaceae F – Z , Springer Verlag, Berlin / Heidelberg / New York 2001, ISBN 3-540-41723-0 .
- Steven A. Hammer: Lithops: Treasures of the Veld (Observations on the Genus Lithops NEBr) . British Cactus and Succulent Society, 1999, ISBN 0-902099-64-7 .
- Rudolf Heine: Lithops - living stones . 2nd edition, Neumann, Leipzig / Radebeul 1990, ISBN 3-7402-0000-6 .
Individual evidence
- ^ William John Burchell: Travels in the interior of southern Africa. Longman, Hurst, Rees, Orme & Brown, London 1822, Vol. 1, p. 310; on-line
- ^ Adrian Hardy Haworth: Saxifragearum enumeratio: Accedunt Revisiones plantarum . London 1821, p. 84 online
- ↑ The Gardeners' Chronicle . Series 3, Volume 71, 1922
- ↑ Lithops . In: 2007 IUCN Red List of Threatened Species . IUCN 2007, accessed October 1, 2008.
further reading
- Harald Jainta, Anja Jainta: Living stones - fascination in southern Africa . In: Cacti and other succulents . Volume 58, No. 4, pp. 99-105, Pforzheim 2007
- Harald Jainta, Anja Jainta: Fascinating living stones in southern Africa . In: Cacti and other succulents . Volume 60, No. 12, pp. 309-318, Pforzheim 2009
- Harald Jainta, Anja Jainta: Living stones in Central and West Namibia . In: Cacti and other succulents . Volume 61, No. 11, pp. 295-303, Pforzheim 2010
- A. Kellner, CM Ritz, P. Schlittenhardt, FH Hellwig: Genetic differentiation in the genus Lithops L. (Ruschioideae, Aizoaceae) reveals a high level of convergent evolution and reflects geographic distribution . In: Plant Biology . Volume 13, Number 2, 2011, pp. 368-380, DOI: 10.1111 / j.1438-8677.2010.00354.x .
