Lactoris fernandeziana
| Lactoris fernandeziana | ||||||||||||
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Illustration of Lactoris fernandeziana |
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| Lactoridaceae | ||||||||||||
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| Lactoris | ||||||||||||
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| Scientific name of the species | ||||||||||||
| Lactoris fernandeziana | ||||||||||||
| Phil. |
Lactoris fernandeziana is a plant species that is endemic to theisland of Robinson Crusoe off Chile . It is the only species of the genus Lactoris and is now either in their own family Lactoridaceae or in the family of aristolochiaceae classified (Aristolochiaceae). Fossil pollen finds that closely resemble the pollen of the species are known from almost every continent. This suggests that the family's range was once significantly larger, but that they then became extinct everywhere except on Robinson Crusoe. The population of the species on this island is estimated at only around 1000 specimens.
description
Vegetative characteristics
Lactoris fernandeziana is a shrub that reaches heights of over 1.50 m. The small and simple leaves are alternate. The leaf blades are inverted ovate, with entire margins and bulging and appear translucent with dots. The stipules are fused with each other and with the axially facing (adaxial) side of the petioles , so that a kind of sheath is formed around the branch.
The branches branch out monopodially , are slightly zigzag-like and have thickened nodes . This thickening is caused by a stronger expression of the medullary and cortical tissue compared to the internodes .
Inflorescences and flowers
The small, threefold flowers stand individually in the armpits or on two- to four-flowered, grape-like short shoots that are not really inflorescences . The flowers can be bisexual or purely female, in the latter case the stamens are only pronounced as staminodes . The female flowers are on average 2.7 mm long, the bisexual flowers on average 3.5 mm. Many authors also state that purely male flowers are formed with stunted pistils , but this could not be confirmed in studies of the location of the plants. Both forms of the flowers occur together on one plant, so that the species is considered to be gynomonic . At the base of the flower stalks is an axially facing bract . The three sepals overlap like roof tiles and are about 2.4 mm long on average. Petals are not formed.
The stamens are in two circles of three pieces each. They are short, have flattened filaments and outward-turned, opening through slots dust bag . The pollen is released in constant tetrads . The inner circle of the stamens, sometimes both circles, are transformed into staminodes. The three carpels are in a single circle and are fused together at the base, but are otherwise free. The ovary tapering into a short style with a run-down scar . In each ovary there are four to eight ovules , which are arranged anatropically.
Fruits and seeds
The fruits are structured like follicles and beaked. They contain small seeds with plenty of oily endosperm and a very small, two cotyledons supporting embryo . The seed coat consists only of a slightly thickened inner wall, the rest of the cell structure has receded.
Other specifications
The chromosome number is 2n = 40, it is assumed that the chromosome set is tetraploid . Phytochemical characteristics are hardly known, only small amounts of kaempferol have been detected.
Occurrence and locations
The species is endemic to the island of Robinson Crusoe , which belongs to the Juan Fernández Islands . It grows there in the forests of the foothills at altitudes between 400 and 600 m.
Usually it can be found in relatively humid locations as an inconspicuous representative of the shrub layer ; it is rarely found in sunny forest clearings. In some cases, the species was already considered extinct or only survived by fewer than 10 specimens, but after expeditions in the early 1990s, the population was estimated at around 1000 specimens. There were fewer than 10 plants at most locations.
ecology
So far, no visitors who could serve as pollinators have been observed on the flowers of Lactoris fernandeziana . This, and the lack of any obvious rewards for pollinators, such as nectar , suggest that pollination is caused by wind or rain. Some early authors suggested that small beetles or flies could be the pollinators.
Systematics
Lactoris fernandeziana was classified into the pepper-like order at an early stage on the basis of morphological features . Molecular biological studies place the species within the order close to the family of aristolochiaceae (Aristolochiaceae). However, it has not yet been possible to precisely determine whether the species can be placed within this family or has developed independently. The Angiosperm Phylogeny Group therefore temporarily recognizes the Lactoridaceae family in the system of bedecktsamer according to APG II from 2003. Contrary to this, Peter Stevens lists the species as part of the Easter fluffy plants on his website, which is based on the APG II system. The 36th edition of the Strasburger published in 2008 leads the species again as an independent family.
A molecular biological study that included 105 taxa from the order of the pepper-like (Piperales) compared Lactoris fernandeziana as a sister clade of the subfamily Aristolochioideae. However, the relationship to the second subfamily of the Osterluze family - the Asaroideae - could not be clarified. Depending on the method used, another hypothesis was put forward about the cladistic relationships:
The first hypothesis , based on the method of parsimonia, divides Lactoris fernandeziana into the easter leek family, the lizard-tail family (Saururaceae) and the pepper family (Piperaceae) in turn form a sister clade:
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According to the cladogram
Investigations according to the Bayesian and the maximum likelihood method , however, contrast the Asaroideae with the Saururaceae and the Piperaceae, which would make the Osterluze family paraphyletic even without the incorporation of Lactoris fernandeziana :
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According to the cladogram
Development history
Fossil pollen grains that can be assigned to the Lactoridaceae are known from South Africa , Canada , the USA , Australia , India , the Antarctic , and Argentina . The oldest come from the Cretaceous Period of South Africa and are dated to an age of 93 to 76 million years. The most recent finds come from the early Miocene of Argentina and are therefore also the closest finds to today's area of distribution.
Since the Juan Fernández Islands are of volcanic origin and only about 4 million years old and have never been connected to other land masses, it is believed that the species is a remnant of an ancient lineage that dates back to the last 4 million years Island, but then became extinct in the rest of the world. It is believed that the Lactoridaceae developed in South Africa and spread from there to America, India, Antarctica and South America during the Cretaceous Period. There are several theories about the exact route of distribution as far as South America, possibly there were also several routes at different times.
Botanical history
The genus Lactoris was first described by Rudolph Amandus Philippi in 1865 with the only species Lactoris fernandeziana . Philippi himself found a single specimen on a four-day expedition to the Juan Fernández Islands in November 1864. The name of the genus is derived from an old Latin name of a plant whose exact identity is not known. The type epithet is derived from the name of the island group on which the plant was found. For a long time Philippi's publication in the booklets on the "Negotiations of the Zoological-Botanical Society in Vienna" was regarded as the first publication that was valid in accordance with the rules of the ICBN . A Spanish-language description in the “Anales de la Universidad de Chile” was published in early June 1865, but the German-language one could not have appeared before August of the same year. The Spanish-language publication is therefore considered a valid first description of Art.
The position of the species in relation to other families has often been interpreted differently by different authors: Philippi himself classified the species in the Magnoliaceae , but mentions that it may represent a family of its own. On the basis of the description written by Philippi in the “Negotiations of the Zoological-Botanical Society in Vienna”, Eduard Fenzl placed the species closer to the rose apple family (Dilleniaceae) in a comment on this publication ; in the "Genera plantarum" by George Bentham and Joseph Dalton Hooker it is classified in the tribe Saurureae (corresponds to the current family of the lizard- tail plants ( Saururaceae)) of the pepper plants (Piperaceae). Philippi's suggestion to place the species in a monotypical family was not followed by Adolf Engler until 1887 when he described the Lactoridaceae family; Like Philippi, he too sees the family close to the magnolia family (Magnoliaceae).
At the end of the 20th century, some systematists also led the species with the status of a monotypical order Lactoridales (systematics according to Rolf and Gertrud Dahlgren ) or even a superordinate order Lactoridanae (systematics according to Armen Tachtadschjan ), but it seems to be included in the order of the pepper-like (Piperales) as secured.
supporting documents
Individual evidence
Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:
- ^ Marcia Ricci: Evaluation of conservation status of Lactoris fernandeziana Philippi (Lactoridaceae) in Chile . In: Biodiversity and Conservation , Volume 10, Number 12, December 2001. pp. 2129-2138. doi : 10.1023 / A: 1013189526734
- ↑ a b c d Gabriel Bernardello et al .: Reproductive Biology of Lactoris fernandeziana (Lactoridaceae) . In: American Journal of Botany , Volume 86, Number 6, 1999. pp. 829-840.
- Jump up ↑ a b c Daniel J. Crawford et al .: Lactoris fernandeziana (Lactoridaceae) on the Juan Fernandez Islands: Allozyme Uniformity and Field Observations . In: Conservation Biology , Volume 8, Number 1, March 1994, pp. 277-280. doi : 10.1046 / j.1523-1739.1994.08010277.x
- ↑ a b Angiosperm Phylogeny Group : An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II . In: Botanical Journal of the Linnean Society , Volume 141, 2003. pp. 399-436.
- ↑ Peter Stevens: Aristolochiaceae . In: Angiosperm Phylogeny Website , accessed July 5, 2009.
- ^ Andreas Bresinsky, Christian Körner, Joachim W. Kadereit, Gunther Neuhaus, Uwe Sonnewald: Strasburger - textbook of botany. Founded by E. Strasburger. Spectrum Akademischer Verlag, Heidelberg, 2008 (36th edition) ISBN 978-3-8274-1455-7
- ↑ a b c Stefan Wanke et al .: Evolution of Piperales — matK gene and trnK intron sequence data reveal lineage specific resolution contrast . In: Molecular Phylogenetics and Evolution , Volume 42, 2007. pp. 477-497. doi : 10.1016 / j.ympev.2006.07.007
- ↑ a b Juan Carlos Gamerro and Viviana Barreda: New fossil record of Lactoridaceae in southern South America: a palaeobiogeographical approach . In: Botanical Journal of the Linnean Society , Volume 158, Number 1, 2008. pp. 41-50. doi : 10.1111 / j.1095-8339.2008.00860.x
- ↑ a b Rudolph Amandus Philippi: About two new plant genera. A letter to Mr. Prof. u. Director Dr. Eduard Fenzl. (PDF; 1.5 MB) In: Negotiations of the Zoological-Botanical Society in Vienna , 1865. pp. 517–524.
- ↑ Thomas G. Lammers and Tod F. Stuessy: Lectotypification of Lactoris fernandeziana Philippi (Lactoridaceae).
- ↑ George Bentham and Joseph Dalton Hooker: Piperacae . In: Genera plantarum , Volume 3, Reeve, London, 1883. p. 127
- ↑ Adolf Engler: About the Lactoridaceae family . In: Botanical Yearbooks for Systematics, Plant History and Plant Geography , Volume 8, Leipzig, 1887. pp. 53–56.
- ↑ James L. Reveal: Validation of Ordinal Names of Extant Vascular Plants . In: Novon , Vol. 2, 1992. pp. 238-240
- ↑ James L. Reveal and Alexander B. Doweld: Validation of Some SupAGENeric Names in Magnoliophyta . In: Novon , Volume 9, 1999. pp. 549-553.
literature
- Klaus Kubitzki et al. (Ed.): The Families and genera of vascular plants , Volume II: Flowering Plants, Dicotyledons. Magnoliid, Hamamelid and Caryophyllid Families , Springer Verlag, 1990, ISBN 978-3-540-55509-4 .
