Geraniums

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Geraniums
Pelargonium cucullatum

Pelargonium cucullatum

Systematics
Nuclear eudicotyledons
Rosids
Eurosiden II
Order : Cranesbill (geraniales)
Family : Cranesbill family (Geraniaceae)
Genre : Geraniums
Scientific name
Pelargonium
L'Hér. ex Aiton

The geraniums ( Pelargonium ) are a genus of flowering plants in the family of geraniaceae (Geraniaceae). The botanical genus name is derived from the Greek word pélargos (πέλαργος) for " stork " and refers to the cranesbill-like elongated shape of the fruit . About 220 to 280 species belong to this genus. The first plant specimens were brought to Europe as early as 1600.

As a common name for certain Pelargonium species and hybrids used as bedding or balcony plants, the name “geranium” is often used (from the Greek word géranos , γέρανος, which means “crane”).

The noble pelargonium hybrid Pelargonium × grandiflorum "Princess Purpurella" was chosen in 2006 and the pelargonium hybrid Pelargonium × hybrida "Baronesse Sophia" in 2011 as the Bavarian balcony plant of the year .

Differences from the genus Geranium

Pelargoniums ( Pelargonium ) differ from the genus of the cranesbills ( geranium ), which is also represented in the Central European flora, in their zygomorphic flower structure. For the species bred as balcony plants, however, the term geranium is still common in Germany , although systematically incorrect.

description

Illustration of Pelargonium drummondii from 1894

Vegetative characteristics

Pelargonium TYPES grow as annual or perennial herbaceous plants , rarely as subshrubs or shrubs ; many species lignify as they get older. Some species are succulent . They contain essential oils . The upper leaves are usually alternate , the lower leaves are usually opposite. The stalked, mostly hairy leaves are simple or compound , mostly lobed to divided. Stipules are present.

Generative characteristics

The flowers are usually grouped together in axillary or terminal, simple or compound, dold-like inflorescences on mostly long inflorescence shafts and often contain bracts .

Flower diagram of Pelargonium zonale

The stalked, hermaphrodite flowers are zygomorphic and fünfzählig double, distinguishable in sepals and petals perianth (perianth). The five sepals are usually not with each other, but partly fused with the flower stalk to form a nectar tube. This nectar tube can be a few millimeters to a few centimeters long. The mostly five (rarely four) petals are mostly free and nailed; the top two are clearly different from the bottom three. In contrast to the other genera of the family, Pelargonium lacks a disc . There are usually two circles with five stamens each, mostly only two to seven are fertile , the others are reduced to staminodes . Five carpels have become a top permanent ovary grown. The five styluses are fused to the tip and form the "beak" with five scars . All species are pre-male , which means that the stigmas do not ripen until after the stamens, to prevent self-pollination .

When ripe, only the inner parts of the carpels remain as a central column. The outer parts, which each enclose a seed at the bottom , stand out. The fruit is a split fruit that pops up into five solitary partial fruits. The mechanism of distribution is the same as that of the cranesbill .

Occurrence

Most Pelargonium species grow in South Africa and Namibia , so they belong to the Cape flora (Capensis). 80% of the species thrive in the southwesternmost area of ​​the Capensis with winter rain. A relatively large number of species extend further north in tropical East Africa to Zimbabwe, Malawi, Tanzania, Kenya, Ethiopia and some species are also found on the Arabian Peninsula (for example in Yemen). There are only a few species outside of the African continent. There are some species in the Middle East : from eastern Turkey to Iraq to Iran. Few species are endemic to Madagascar ( Pelargonium caylae Humbert, Pelargonium madagascariense Baker). There is one species each on the islands of St. Helena ( Pelargonium cotyledonis (L.) L'Herit.) And Tristan da Cunha ( Pelargonium acugnaticum Thouars). There are few species in Australia , Tasmania , northern New Zealand and some islands in the Indian Ocean .

Pelargonium species colonize a multitude of habitats, water margins as well as the dry Namib desert , rocky mountain peaks as well as coastal dunes. Some species are succulent and have organs above or below ground for storing water.

The pelargoniums cultivated in Central Europe as bedding and balcony plants are hybrids of various wild species from the Cape, Capensis , South Africa , especially Pelargonium zonale and Pelargonium inquinans (standing geranium zonale hybrids) and Pelargonium peltatum (hanging geranium Peltatum hybrids). Most of the cuttings in Switzerland are imported by air transport. As soon as the majority of the added value has been generated in Switzerland, the pelargoniums can still be sold as local.

Systematics

Already in 1732 Johann Jacob Dillen called plants of South African origin, which he saw in William Sherard's garden in Eltham, as pelargonium in his work Hortus Elthamensis . In 1738 Johannes Burman published his outstanding work on African plants, Rariorum Africanarum Plantarum . He also uses the term pelargonium for plants from South Africa. Carl von Linné and subsequent botanists, however, called these plants all geranium . Only with the publication of the first description of the genus Pelargonium 1789 by de Charles Louis L'Héritier breeding Elle by William Aiton genus was established. As a type of plant, JJA van der Walt established Geranium cucullatum L., first described by Linné in 1753, as the lectotype .

Synonyms for the genus are Dimacria Sweet (1820), Hoarea Sweet (1820), Otidia Sweet (1820), Phymathanthus Sweet (1820), Ciconium Sweet (1821), Jenkinsonia Sweet (1821), Campylia Sweet (1824), Seymouria Sweet ( 1824), Grenvillea Sweet (1825), Chorisma Ecklon & Zeyher (1835), Cortusina Ecklon & Zeyher (1835), Dibrachya Ecklon & Zeyher (1835), Eumorpha Ecklon & Zeyher (1835), Isopetalum Ecklon & Zeyher (1835), Ligularia Ecklon & Zeyher (1835, nom. Illeg. ICBN Article 53.1), Myrrhidium Ecklon & Zeyher (1835), Peristera Ecklon & Zeyher (1835), Polyactium Ecklon & Zeyher (1835) and Polyschisma Ecklon & Zeyher (1859).

The genus Pelargonium ( Pelargonium ) distinguishes between 200 and 280 species and is divided into the following 16 sections (species selection and section affiliation according to GRIN):

Campylia section : Pelargonium tricolor
Section Chorisma : Zygomorphic flowers of Pelargonium tetragonum
Ciconium section : Pelargonium acetosum
Section of Cortusina : Pelargonium echinatum
Hoarea section : Pelargonium oblongatum
Section Isopetalum : inflorescence of Pelargonium cotyledonis
Section Jenkinsonia : Pelargonium endlicherianum
Ligularia section : inflorescence of Pelargonium appendiculatum
Otidia section : Pelargonium alternans
Section Otidia : The stem succulent Pelargonium carnosum
Otidia section : Pelargonium dasyphyllum
Section Otidia : Pelargonium klinghardtense
Pelargonium section : population of Pelargonium capitatum
Pelargonium section : Pelargonium cordifolium
Peristera section : Pelargonium glechomoides
Polyactium section : habit and inflorescence of Pelargonium bowkeri
Polyactium section : Pelargonium triste
Reniformia section : Pelargonium sidoides
Pelargonium campestre

About 20 species are currently not assigned to any of the above sections.

use

Ornamental plant

range

Due to intensive breeding work, six important groups of pelargoniums have emerged, which are of great importance for the flower trade:

  • Pelargonium zonal hybrids that have almost circular leaves. Most of the upright cultivars belong to this group.
  • Pelargonium Zonal Hybrid

  • Section of an inflorescence

  • Inflorescence and leaves

  • inflorescence

  • Pelargonium peltatum hybrids, in contrast to zonal hybrids with smooth, waxy leaves and semi-pendulous to pendulous growth.
  • Pelargonium-peltatum hybrid

  • Inflorescence and leaves

  • On a balcony

  • inflorescence

Variety of the Pelargonium grandiflorum hybrids
  • Edelpelargonien - the cultivated as houseplants Edelpelargonien (also English geraniums or Regalpelargonien) come mainly from Pelargonium cucullatum and Pelargonium grandiflorum hybrids from.
  • Unique pelargonium
  • Angel pelargoniums
  • Scented pelargonium , for example ( Pelargonium odoratissimum ), some of which are also of breeding origin. However, there are also wild species in culture, most commonly Pelargonium graveolens , the “lemon geranium”. In tropical and subtropical areas, some species are grown on a large scale for the production of orange oil.
Pelargonium variety, chromolithography

The first South African pelargoniums were imported into Europe at the beginning of the 17th century, and for almost 200 years they were one of the most important groups of plants in the court orangeries - some of the collections contained hundreds of species and varieties . Today geraniums are among the most economically important crops for growing ornamental plants.

Many gardening enthusiasts are particularly familiar with the pelargoniums of the Zonale and Peltatum hybrids. As a result of breeding work, there are now many hundreds of varieties within these two species that differ in flower color and foliage. Thus, the zonal hybrids and the peltatum hybrids belong to the most important horticultural plants in the group of bedding and balcony plants. In Kleve on the Lower Rhine, Syngenta Seeds GmbH (one of the largest pelargonium growers and producers of young plants in the world) has a pelargonium museum with around 170 wild species.

wintering

The perennial plants can easily be brought over winter in Europe and often bloom a little less in the following year. To do this, the plants are dug up in September or October, the roots are reduced somewhat, the plant itself is cut back about eight centimeters on the main trunk. The new shoots drift from this stump. The plants are stored in a moist substrate in a cool and dark cellar. From the end of February or March, they are best placed on the windowsill and watered more heavily, moderate watering is sufficient during the winter months. Depending on the weather and if there is no frost, the plants can be put outside in mid-May.

Medical use

Medicines for the treatment of common colds are made from the roots of the species Pelargonium sidoides .

Geranium essential oil

An essential oil , geranium oil, is obtained from various types of scented geraniums, but above all from the rose geranium ( Pelargonium graveolens ) by steam distillation . The ingredients of the oil, which mainly consists of monoterpene compounds , differ depending on the cultivation area of ​​the varieties used . Geranium oil is mainly used in the perfume industry.

Use in the kitchen

The rose pelargonium ( Pelargonium graveolens ), some other Pelargonium species and varieties from the group of scented pelargoniums are also used in food preparation. They are used to flavor drinks, desserts and preserves.

literature

  • Matija Strlic: The Pelargonium Page. (Section description and systematics: a lot of information on the genus and the delimitation to the other genera of the family.)
  • JJ Van der Walt: Pelargoniums of southern Africa. Purnell, Cape Town, 1977.
  • RTF Clifton: Geraniales - The species check list. Part 4: Pelargonium. 5th edition, Geraniaceae Group, Dover, England 2004, ISBN 1-899742-60-3 .

Single references

  1. ↑ Balcony design and terrace design with potted flowers . ( Online ).
  2. ↑ Baptism of the Bavarian balcony plant of the year 2011 in Middle Franconia . ( Online ( Memento from May 13, 2014 in the Internet Archive ) (PDF; 176 kB)). Baptism of the Bavarian balcony plant of the year 2011 in Middle Franconia ( Memento of the original from May 13, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.aelf-fu.bayern.de
  3. ↑ Matija Strlic: The Pelargonium Page : A lot of information about the genus and the delimitation to the other genera of the family (English)
  4. ↑ Marianne Kägi: Geranium production - Swiss geraniums without Swiss roots. In: srf.ch . May 8, 2019, accessed May 8, 2019 .
  5. ^ William Aiton: Hortus Kewensis; or, a Catalog of the Plants Cultivated in the Royal Botanic Garden at Kew . Volume 2, London 1789, p. 417 ( online ).
  6. ^ JJA van der Walt: Notes on the nomenclature of Pelargonium (Geraniaceae). In: Journal of South African Botany. Volume 45, July 1979, pp. 377-380.
  7. ↑ F. Albers: Pelargonium : In: Urs Eggli (Ed.): Sukkulentenlexikon. Dicotyledons (dicotyledons). Eugen Ulmer, 2002, p. 260.
  8. ^ Pelargonium in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  9. ↑ Entry on geranium oil. In: Römpp Online . Georg Thieme Verlag, accessed on June 17, 2014.
  10. ↑ Avril Rodway: Herbs and Spices. The most useful plants in nature - culture and use. Tessloff Verlag, Hamburg 1980, ISBN 3-7886-9910-8

Web links

Commons : Pelargonium ( Pelargonium )  - Collection of images, videos and audio files
Wiktionary: Pelargoniums  - explanations of meanings, word origins, synonyms, translations