Petunia
Petunia × hybrida
The petunia ( Petunia ) are a genus of the nightshade family (Solanaceae ). Your are attributed to 16 species whose home is located in the temperate to subtropical areas of South America. The Garden Petunia ( Petunia × hybrida ) is a line drawn from several species of the genus hybrids and one of the most important ornamental plants.
- 7.1 Notes and references
- 7.2 Literature
Description
Petunias are herbaceous plants that are hairy with simple, often sticky trichomes. The leaves are in pairs or alternate. They are simple and entire, and can be pedunculated or sessile. Stems and leaves contain neither crystal sand still drusen ( deposits in plant cells), as is the case with some other genera of the Solanaceae. The pericycle is fibrous, but not the inner and outer phloem. In the deciduous leaves and stems were Petuniasteroide - from ergostane derived C28 steroids - evidence. The fabrics protect plants from the feeding caterpillars.
The flowers appear singly in input time zymösen inflorescences and are accompanied by a pair of nearly equal bracts. You are fünfzählig, almost radial symmetry, fragrant and often dyed striking. The buds coverage is imbricate ( imbrikat ). The calyx is deeply divided. The crown is funnel-shaped or cup-shaped. Within the genus has only Petunia axillaris completely white crowns, with all other species, they are reddish - purple, red or pale blue. The colors of the crowns are due to different anthocyanins. The anthers open by longitudinal slits. The ovary consists of two compartments.
The fruits are dehiscent capsules scheidewandspaltig with two chambers. They contain a large number of tiny, round or angled seeds. The surface of the seed is like a net. This structure is due to the seed surface is perpendicular to the walls that are corrugated in all species. The seeds contain a straight embryo cotyledons are shorter than the rest of the embryo.
The chromosome number is 2n = 14
Occurrence
All species are native to the temperate to subtropical South America. They are found in Brazil, Uruguay, Argentina, Paraguay and Bolivia. The most widely used has Petunia axillaris, which is found in the southern Rio Grande do Sul, in Uruguay, the northern half of Argentina, the center of Paraguay and southern Bolivia.
A large number of species is endemic to Brazil: Petunia mantiqueirensis in southern Minas Gerais, Petunia scheideana, Petunia reitzii and Petunia saxicola in Santa Catarina, Petunia altiplana and Petunia bonjardiensis in the highlands of Santa Catarina and the opposite areas in Rio Grande do Sul, Petunia littoralis and Petunia integrifolia subsp. depauperata in the eastern coastal areas of Santa Catarina and Rio Grande do Sul, Petunia exserta; Petunia Petunia riograndensis and bajeensis occur in the southern Rio Grande do Sul. Petunia Petunia guarapuavensis interior and come in the highlands of Paraná and Santa Catarina, but also in the north-eastern Argentina, Misiones ago.
Another way of Petunia occidentalis, occurs in northwestern Argentina and southern Bolivia.
Ecology
The petunias have adapted in different ways to three different types of pollinators: At pollination by bees ( Melittophilie ) the flowers of Petunia integrifolia and other species are adapted; they are purple, smell hardly produce little nectar and have a wide corolla tube, in which the bees can crawl to get to the nectar or pollen. The white crown of Petunia axillaris with narrow Kronröhren and abundant nectar at night emanating a strong scent, they are adapted to pollination by moth ( Sphingophilie ). At pollination by hummingbirds ( Ornithophilie ) the flowers of petunia exserta adapted: The crown is red, the Corolla lobe are bent back and dust bag and pen stand out from the flower. The flowers are fragrant little, but have a long corolla tube and form abundant nectar.
System
Outer systematics
The genus Petunia is traditionally classified within the scheme of the nightshade family in the tribe Nicotianeae and there in the subtribe Nicotianinae. Molecular biological studies have shown, however, that the Petunia not with the kind of tobacco (Nicotiana ) can be grouped into a common clade. In the scheme of family after Richard Olmstead in 2007, the genus is classified together with the Bouchetia, Brunfelsia, Calibrachoa, Fabiana, Hunzikeria, Leptoglossis, Nierembergia and Plowmania in a designated as Petunieae clade.
For a long time the genus Calibrachoa was also counted among the Petunia. Through studies of kinship relations between the two genera with morphological and molecular biological methods could be found that both genera are monophyletic and the division of the genus is therefore justified.
Inside systematics
Within the genus Petunia currently recognized 14 species:
- Petunia altiplana T. Ando & Hashim.
- White-flowered petunia ( Petunia axillaris ( Lam.) Britton, Sterns & Poggenb. ) Petunia axillaris subsp. axillary
- Petunia axillaris subsp. parodii ( Steere ) Cabrera
- Petunia axillaris subsp. subandina T. Ando
- Petunia integrifolia subsp. integrifolia
- Petunia integrifolia subsp. depauperata R.E.Fr.
Molecular biological studies within the genus showed that Petunia axillaris with all three subspecies, Petunia Petunia occidentalis exserta and together form a monophyletic group, which are compared with the remaining species of the genus.
The following types were assigned according to morphological features of the genus Calibrachoa, but not yet moved to the rules of biological nomenclature in this genus:
- Petunia alpicola L.B.Sm. & Downs
- Petunia helianthemoides Sendtn.
- Petunia kleinii L.B.Sm. & Downs
- Petunia ledifolia Sendtn.
- Petunia pubescens ( Spreng. ) R.E.Fr.
- Petunia variablis R.E.Fr.
Botanical history
The first description of the genus Petunia is by Antoine- Laurent de Jussieu in the year 1803. The name is derived from Petun, the word of the Brazilian natives for tobacco. Jussieu described with the genus also the two types Petunia Petunia parviflora and nyctaginiflora. The latter, however, was described in 1793 by Jean -Baptiste de Lamarck as Nicotiana axillaris, so Petunia axillaris is the valid name of this species. The last full revision of the genus in 1911 was carried out by Robert Elias Fries, the difference in total 27 species, of which he published the first description to twelve types. The determination of the type species of the genus comes from Nathaniel Lord Britton and Addison Brown, in 1913 the first mentioned of Jussieu kind, so Petunia parviflora chose.
1985 published HJW Wijsman and JH de Jong an investigation on the basis of it, defined two groups within the genus Petunia, as it was understood in the sense of Jussieu, suggesting as an independent species. They transferred species with a chromosome number of 2n = 14 in the genus Stimoryne, a name that was introduced in 1836 by Constantine S. Rafinesque - Schmaltz, and maintained the remaining species with a chromosome number of 2n = 18, together with the then valid type species Petunia parviflora in the genus Petunia. However, this would have meant that the Petunia × hybrida Gartenpetunie would no longer belongs to the genus Petunia. To circumvent this problem, suggested Onno Winjands et al. 1986, a preservative before the name Petunia, by the second named of Jussieu type is used as a type species, although according to the rules of the ICBN always needs to be taken as first described as lectotype species of a genus. The next valid name for the rest of the genus in the sense Jussieu Calibrachoa is specified, this name was in 1825 by Pablo de La Llave and Juan José Martinez de Lexarza for Calibrachoa procumbens (now a synonym for Calibrachoa parviflora ) were used. Also in view of the unusual nature of this approach was the proposal by Wijnands et al. adopted by the Committee for Spermatophyta with a vote of 10:1.
However, the work of the research group led by Wijsman assigned to only a portion of the known species of the one or the other class, so that at first the exact scope of Petunia and Calibrachoa was not defined. Other researchers - João Renato Stehmann and William D' Arcy - took these assignments before in the sequence and transferred more species to the genus Calibrachoa. Five species that are morphologically assigned to the Calibrachoa and a chromosome number of 2n = 18 have, however, the genus have not yet been formally assigned.
Use
Petunias belong because of their large, open flowers in various colors to the most popular ornamental plants. The first kind is drawn in Culture 1823 have been Petunia axillaris, in 1825 a review of this type in " Curtis 's Botanical Magazine " was published. The second cultivated species, Petunia integrifolia, bloomed in July 1831 for the first time in the Botanical Gardens of Glasgow.
The available today Garden Petunia ( Petunia × hybrida ) is a hybrid of these two species. However, the exact origin of the hybrids can no longer be traced, an edition of the " Curtis 's Botanical Magazine " of 1918 refers to the fact that the original seeds have been bought in 1834 by a breeder named Atkins from Northampton. In addition, the breeder Ernst Benary of Erfurt, the then largest significance is attributed as a breeder of petunias. The different varieties are traditionally divided into four groups of varieties, of which ' Grandiflora ' and ' Multiflora ' are the most important.