Gazania

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Gazania
Gazania rigens var. Rigens

Gazania rigens var. Rigens

Systematics
Euasterids II
Order : Astern-like (Asterales)
Family : Daisy family (Asteraceae)
Subfamily : Cichorioideae
Tribe : Arctotideae
Genre : Gazania
Scientific name
Gazania
Garden.

The Gazania ( Gazania ), also called midday gold , midday gold flowers and sun talers , are a genus of plants in the subfamily of the Cichorioideae within the sunflower family (Asteraceae). The 19 or so species are mainly distributed in southern Africa in Namibia and South Africa. It is one of the many genera whose species are called ice flowers. There are many varieties, these are hybrids ( Gazania hybrids) of several species ( e.g. Gazania rigens , Gazania longiscapa ), which are used worldwide as ornamental plants in parks and gardens.

description

Illustration from Favorite flowers of garden and greenhouse of the subshrub gazanie ( Gazania rigens )
Achene with hair and pappus from Gazania linearis
Flower head of a variety of Gazania rigens

Vegetative characteristics

Gazania are annual or perennial herbaceous plants , rarely half-shrubs , which usually remain low and rarely reach stature heights over 30 (5 to 35) centimeters. They often form lawns. Few species produce white milky juice . The mostly upright shoot axes are often ± compressed. The “root stocks” of the perennial species are often lignified.

Most of the time, foliage leaves are only formed at the base, sometimes there are also leaves distributed along the stem axis. The leaves are stalked or sessile. The leaf blades are linear to lanceolate, spatulate or inverted-lanceolate. The underside of the leaf is usually hairy white woolly. The upper side of the leaf is usually bald or bald, sometimes hairy like a cobweb.

Generative characteristics

The cup-shaped inflorescences are usually single on long stems. The envelopes (involucre) are seldom 5 to mostly 10 to 15 or more millimeters in diameter ± bell-shaped, gyratory or cylindrical. Arranged in two to four rows bracts are grown on 1/2 to 3/4 of their length. The bracts have a ± dry-skinned edge, pointed upper ends and their underside is mostly bald or rarely covered in cobweb-like to woolly hair. The conical or convex basket floors are deeply honeycombed (alveolate).

The flower heads contain ray flowers (= ray flowers) and tubular flowers (= disc flowers). The zygomorphic ray florets are sterile. The white, yellow to cream and orange to red and maroon ray florets usually have a stripe on the underside and a darker spot on the top or on both sides. The crown tongues have five nerves and usually end with four crown teeth, which are often not easily recognizable. The radially symmetrical tubular flowers are all hermaphroditic and fertile. The five yellow to orange petals of the tubular flowers have grown together to form a tube.

The obovate achenes have no ribs and are shaggy hairy; these hairs can cover the pappus ±. The durable pappus consists of seven to eight, rarely up to twelve lanceolate to sub-awn-shaped scales in two rows.

Sets of chromosomes

The basic chromosome number is x = 9; in the natural forms there is diploidy with a chromosome number of 2n = 18.

ecology

This genus bears the common name for midday flowers because its flowers , here the flower heads, just like all other plant species that bear this common German name, open around noon; in fact, they are only fully open when the sun is shining on them.

Systematics, botanical history and distribution

External system

The genus Gazania belongs to the subtribe Gorteriinae from the tribe Arctotideae . In this subtribe the closest related genera are Hirpicium and Gorteria .

Gazania jurineifolia
Gazania krebsiana in the habitat in Namaqualand , South Africa
Gazania krebsiana in habitat in South Africa
Gazania lichtensteinii at the natural site (Goegap NR, Namaqualand, South Africa)
Habit of Gazania linearis
Flower heads of Gazania pectinata
Gazania rigens var. Leucolaena
Gazania rigens var. Uniflora , the flower heads are only open when the sun is shining, hence the name ice plant. In order to avoid confusion with species of the unrelated family of the midday flowers, they should better be named as midday goldflowers.
Gazania rigida

Botanical history

The genus Gazania was established in 1791 by the German botanist Joseph Gaertner in De Fructibus et Seminibus Plantarum , Volume 2. The botanical generic name Gazania honors Theodoros Gazes (1400-1475), who translated the botanical works of Theophrastus of Eresos from Greek into Latin . Another explanation for the name reads: Greek gaza for rich (for the abundance of colors in this genus); but it is incorrect. A synonym for Gazania Gaertn. nom. cons. is Melanchrysum Cass.

Many of the Gazania species are difficult to distinguish, and the number of species is given differently by each author.

In 1959 Helmut Roessler published a revision of the genus Gazania with 16 species. In 1973 he published some additions to his treatise.

Molecular genetic data ( chloroplasts - and nuclear - DNA sequences of all types Roessler's except Gazania othonnites ) published Howis et al. 2009 a phylogeny of the genus Gazania . Howis et al. found that eight species form a species complex . The seven species that do not belong to this species complex are: Gazania caespitosa , Gazania ciliaris , Gazania heterochaeta , Gazania jurineifolia , Gazania lichtensteinii , Gazaniaschenckii and Gazania tenuifolia .

By Magee et al. Two more species were first described in 2011 and a new identification key for all Gazania species was published.

Species and their distribution

The Gazania species are important floral elements of the Capensis . The areas of most taxa are limited to southern Africa, for example Botswana , Namibia , Lesotho and South Africa . Only one subspecies ( Gazania krebsiana subsp. Serrulata ) occurs in tropical Africa in Tanzania , Angola , Malawi , Mozambique , Zambia and Zimbabwe .

There are about 19 (16 to 40) species in the genus Gazania :

  • Gazania caespitosa Bolus It is only known from the collection of types in 1872. The location was given too imprecisely with " Koudeveld Mountains (Sneeuberge) west of Graaff-Reinet " in Eastern Cape .
  • Gazania ciliaris DC. It only occurs in the Western Cape .
  • Gazania heterochaeta DC. : It occurs in southern Africa from Namibia to the South African provinces of the Western and Northern Cape .
  • Gazania jurineifolia DC. : There are two subspecies:
    • Gazania jurineifolia DC. subsp. jurineifolia : It is common in the South African provinces of the Free State , Eastern, Northern and Western Cape.
    • Gazania jurineifolia subsp. scabra (DC.) Roessler (Syn .: Gazania scabra DC. , Gazania pinnata var. scabra (DC.) Harv. , Gazania varians Dinter , Gazania violacea Muschl. ex Engl. & Drude ): It occurs in Namibia and the North Cape .
  • Crab Gazania ( Gazania krebsiana Less. ): There are three subspecies:
    • Gazania krebsiana subsp. arctotoides (Less.) Roessler (Syn .: Gazania arctotoides Less. , gazania leptophylla DC. , gazania longifolia Less. , Gazania pavonia var. zeyheri Harv. , gazania rogersii S.Moore ): She's in Botswana and in South African provinces Free State, Limpopo , Mpumalanga , North West , Eastern, Northern and Western Cape.
    • Gazania krebsiana Less. subsp. krebsiana (Syn .: Gazania lineariloba DC. , Gazania mucronata DC. , Gazania oxyloba DC. , Gazania varians DC. ): It is widespread in Lesotho and in the South African provinces of the Free State, KwaZulu-Natal , the Northern and Western Cape.
    • Gazania krebsiana subsp. serrulata (DC.) Roessler (Syn .: Gazania bracteata N.E.Br. , Gazania canescens Harv. , Gazania montana Spreng. , Gazania serrulata DC. , Gazania schinzii O.Hoffm. , Gazania pygmaea Sond. , Gazania pygmaea var. maculata NEBr. , Gazania pygmaea Sond. Var. Pygmaea , Gazania pygmaea var. Superba N.E.Br. ): It is in Tanzania , Angola , Malawi , Mozambique , Zambia , Zimbabwe , Botswana, Swaziland, Lesotho and in the South African provinces of Free State, KwaZulu-Natal , Gauteng , North West, Eastern, Northern and Western Cape widely used.
  • Gazania lanata Magee & Boatwr. : It was first described in 2011 and so far is only known from the type location above dolomite rock near Robertson in the Western Cape.
  • Gazania leiopoda (DC.) Roessler (Syn .: Gazania pinnata var. Leiopoda DC. ) It occurs in the South African provinces of the Northern and Western Cape.
  • Gazania lichtensteinii Less. (Syn .: Gazania araneosa DC. ): It occurs in southern Africa from Namibia to the South African provinces of Western and Northern Cape.
  • Bristly-scaly gazanie ( Gazania linearis (Thunb.) Druce , Syn .: Gorteria linearis Thunb. ): There are two varieties:
    • Gazania linearis (Thunb.) Druce var. Linearis (Syn .: Arctotis staticefolia Poir. , Gazania kraussii Sch.Bip. , Gazania longiscapa DC. Var. Longiscapa , gazania multijuga DC. , Gazania subulata R.Br. , Gazania pinnata var. multijuga (DC.) Harv. ): It occurs in Lesotho and in the South African provinces of KwaZulu-Natal, Eastern and Western Cape.
    • Gazania linearis var. Ovalis (Harv.) Roessler (Syn .: Gazania longiscapa var. Ovalis (DC.) Harv. , Gazania pottsii L. Bolus ) It occurs only in the Eastern Cape.
  • Gazania maritima Levyns It occurs in the South African provinces of Western and Northern Cape.
  • Gazania othonnites (Thunb.) Less. (Syn .: Gazania intrusa E.Mey. Ex DC. , Gorteria othonnites Thunb. ) It occurs in the South African provinces of the Western and Northern Cape.
  • Gazania pectinata (Thunb.) Spreng. (Syn .: Gazania pinnata var. Grandis (DC.) Harv. , Gazania pinnata var. Speciosa (Willd.) Harv. , Gazania speciosa (Willd.) Less. Gorteria pectinata Thunb. ) It occurs only in the Western Cape.
  • Semi-shrub gazanie ( Gazania rigens (L.) Gaertn. , Syn .: Gorteria heterophylla Willd. , Gorteria pavonia Andrews , Gorteria rigens Thunb. , Gorteria uniflora L. f. , Othonna rigens L. , Gazania leucolaena DC. , Gazania pavonia R .Br. , Gazania pavonia R.Br. var. Pavonia , Gazania splendens Hend. & AAHend. , Gazania splendens Lem. , Gazania uniflora (L. f.) Sims , Gazania uniflora (L. f.) Sims var. Uniflora ) : There are three varieties:
    • Gazania rigens (L.) Gaertn. var. rigens (Syn .: Gazania × splendens Hend. & AAHend. ) It is only known from culture.
    • Gazania rigens var. Leucolaena (DC.) Roessler (Syn .: Gazania leucolaena DC. , Gazania uniflora var. Leucolaena (DC.) Harv. ) It thrives in South Africa only along the coast from the eastern part of the Western Cape to the western part of the Eastern Cape.
    • Gazania rigens var. Uniflora (L. f.) Roessler It is distributed from southern Mozambique and Swaziland and in South Africa from Knysna in the Western Cape along the coast to Eastern Cape and KwaZulu-Natal.
  • Gazania rigida (. Burm f.) Roessler (Syn .: Arctotis rigida Burm f.. , Gazania pavonia var. Hirtella (DC) Harv.. ): It comes in Southern Africa from Namibia to the South African provinces of West and Northern Cape before .
  • Gazaniaschenckii O. Hoffm. (Syn .: Gazania aculeata Muschl. Ex Dinter , Gazania suffruticosa Muschl. ): It occurs in southern Africa from Namibia to the North Cape.
  • Gazania serrata DC. (Syn .: Gazania pinnata var. Serrata (DC.) Harv. ): It occurs in the South African provinces of Western and Northern Cape.
  • Gazania splendidissima Mucina, Magee & Boatwr. : It was first described in 2011. This endemic only thrives on the coast from Port Nolloth to Hondeklipbaai in the North Cape.
  • Gazania tenuifolia Less. : It occurs in southern Africa from Namibia to the South African provinces of the Western and Northern Cape.
  • Gazania thermalis Dinter This endemic occurs only in Namibia. In 2004 it wasrated “Critically Endangered” inthe IUCN's Red List of Endangered Species, and renewed monitoring is required. Only three sites are known, but the authors assume that there could be more sites. They only thrive in hot, brackish springs. These habitats are particularly affected by damage caused by treading. In2004, only 250 flowering specimens were foundin the largest known population .

use

Lush flowering stock of the 'Sun Gold' variety from the 'Sun' variety group

Many varieties of Gazania hybrids are usually grown as annual bedding and balcony plants. Many varieties are grown from seeds, but there are also varieties that are propagated from cuttings .

Variety groups

There are several groups of varieties, each with a wide range of colors (selection):

  • 'Fiesta'
  • 'Sun'
  • 'Talent'
  • 'Mini star'

Invasive plant

From parks and gardens, some species and varieties have spread as invasive plants, particularly in subtropical areas, for example in Australia and California .

swell

  • Theodore M. Barkley, Luc Brouillet, John L. Strother: Asteraceae, tribe Cichorieae. : Gazania , page 196 - same text online as the printed work , In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico. Volume 19: Magnoliophyta: Asteridae, part 6: Asteraceae, part 1 (Mutisieae – Anthemideae). Oxford University Press, New York and Oxford, 2006. (Description section)
  • Seranne Howis: A taxonomic revision of the southern African endemic genus Gazania (Asteraceae) based on morphometric, genetic and phylogeographic data. “Submitted in Fulfillment for the Degree of Doctor of Philosophy” at Rhodes University, March 2007. Full text PDF. (Section systematics)

Individual evidence

  1. ↑ a b c d e f g h i j k l m Theodore M. Barkley, Luc Brouillet, John L. Strother: Asteraceae, tribe Cichorieae. : Gazania , page 196 - same text online as the printed work , In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico. Volume 19: Magnoliophyta: Asteridae, part 6: Asteraceae, part 1 (Mutisieae – Anthemideae). Oxford University Press, New York and Oxford, 2006.
  2. ↑ Vicki A. Funk, Raymund Chan: Phylogeny of the Spiny African Daisies (Compositae, tribe Arctotideae, subtribe Gorteriinae) based on trnL-F, ndhF, and ITS sequence data. In: Molecular Phylogenetics and Evolution , Volume 48, Issue 1, 2008, pp. 47-60.
  3. ↑ Lotte Burkhardt: Directory of eponymous plant names. Botanic Garden and Botanical Museum Berlin, Free University Berlin Berlin 2016 ISBN 978-3-946292-10-4 . doi : 10.3372 / epolist2016
  4. ↑ a b c Seranne Howis, Nigel P. Barker, Ladislav Mucina: Globally grown, but poorly known: species limits and biogeography of Gazania Gaertn. (Asteraceae) inferred from chloroplast and nuclear DNA sequence data. In: Taxon , Volume 58, Issue 3, 2009, pp. 871-882. Full text online.
  5. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac Christiana Flann (Ed.), 2009+: Global Compositae Checklist .
  6. ↑ Helmut Rössler: Revision of the Arctotideae - Gorteriinae (Compositae). In: Mitteilungen der Botanische Staatssammlung München , Volume 3, 1959, pp. 71–500.
  7. ↑ Helmut Roessler: Mitteilungen der Botanische Staatssammlung Muenchen , Volume 11, 1973, pp. 91–99.
  8. ↑ a b c AR Magee, JS Boatwright, L. Mucina: Gazania lanata and G. splendidissima: two new species of Asteraceae (tribe Arctotideae) from the Greater Capensis, with an updated key for the genus. In: South African Journal of Botany , Volume 77, 2011, pp. 86-93.
  9. ↑ a b c d e f Gazania in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  10. ↑ a b c d e f g h i j k l m n o p q r s t u v w List of species for Gazania in the Red List of South African Plants
  11. ↑ Gazania thermalis in the IUCN Red List of Threatened Species 2017.3. Posted by: P. Craven, S. Loots, 2004. Retrieved April 5, 2018.

Web links

Commons : Gazania ( Gazania )  - Collection of pictures, videos and audio files