Osteospermum ,[ Sunset Western Garden Book, 1995:606–607] is a genus of belonging to the Calenduleae, one of the smaller tribes of the sunflower/daisy family Asteraceae.
In horticulture, several widely cultivated species continue to be sold, grown and referred to as Osteospermum, however some of these species have been scientifically reclassified as being members of the genus Dimorphotheca, including Dimorphotheca barberae (synonym Osteospermum barberae);
Description
Their alternate (rarely
opposite leaves)
Leaf are green, but some variegated forms exist. The leaf form is lanceolate. The leaf margin is entire, but hardy types are toothed.
The daisy-like pseudanthium flower consists of disc florets and ray florets, growing singly at the end of branches or sometimes in inflorescences of terminal corymbose cymes. The disc florets are pseudo-bisexual and come in several colors such as blue, yellow and purple. The hardy types usually show a dark blue center in the disc until the yellow pollen is shed. The ray florets are female and are found in diverse colors such as white, cream, pink, purple, mauve, and yellow. Some have "spooned" petals such as "Pink Whirls".
Taxonomy
The genus
Osteospermum was named by
Carl Linnaeus in 1753. The scientific name is derived from the Greek
osteon (bone) and Latin
spermum (seed). Plants of the World Online and the South African National Biodiversity Institute accept a broad definition of the genus, which is a sister taxon to
Dimorphotheca. Other authorities treat its generic synonyms (
Chrysanthemoides,
Oligocarpus, etc.) as separate genera.
[Wessel Swanpoel, Vera de Cauwer and Abraham E. Van Wyk (2020) A new species of Osteospermum subgen. Tripteris
]
/ref>
Species
74 species are accepted:
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Osteospermum acanthospermum
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Osteospermum aciphyllum
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Osteospermum afromontanum
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Osteospermum amplectens
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Osteospermum angolense
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Osteospermum apterum
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Osteospermum armatum
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Osteospermum asperulum
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Osteospermum attenuatum
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Osteospermum auriculatum
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Osteospermum australe
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Osteospermum bidens
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Osteospermum bolusii
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Osteospermum breviradiatum — Lemoenboegoe
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Osteospermum burttianum
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Osteospermum calcicola
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Osteospermum calendulaceum — Stinking Roger
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Osteospermum ciliatum
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Osteospermum connatum
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Osteospermum corymbosum
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Osteospermum crassifolium
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Osteospermum dentatum
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Osteospermum elsieae
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Osteospermum grandidentatum — Yellow trailing daisy
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Osteospermum grandiflorum
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Osteospermum hafstroemii
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Osteospermum herbaceum
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Osteospermum hirsutum
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Osteospermum hispidum
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Osteospermum hyoseroides
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Osteospermum ilicifolium
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Osteospermum imbricatum
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Osteospermum incanum
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Osteospermum junceum
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Osteospermum karrooicum
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Osteospermum lanceolatum
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Osteospermum leptolobum
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Osteospermum microcarpum
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Osteospermum microphyllum
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Osteospermum moniliferum
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Osteospermum monocephalum
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Osteospermum monstrosum
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Osteospermum montanum
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Osteospermum muricatum
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Osteospermum namibense
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Osteospermum nervosum
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Osteospermum nordenstamii
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Osteospermum norlindhianum
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Osteospermum nyikense
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Osteospermum oppositifolium
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Osteospermum pinnatilobatum
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Osteospermum pinnatum
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Osteospermum polycephalum
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Osteospermum polygaloides
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Osteospermum potbergense
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Osteospermum pterigoideum
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Osteospermum pyrifolium
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Osteospermum rigidum
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Osteospermum rosulatum
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Osteospermum rotundifolium
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Osteospermum sanctae-helenae
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Osteospermum scariosum
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Osteospermum sinuatum
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Osteospermum spathulatum
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Osteospermum spinescens
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Osteospermum spinigerum
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Osteospermum spinosum
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Osteospermum striatum
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Osteospermum subulatum
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Osteospermum thodei
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Osteospermum tomentosum
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Osteospermum triquetrum
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Osteospermum vaillantii
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Osteospermum volkensii
Formerly placed here
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Dimorphotheca barberae — synonym Osteospermum barberae )
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Dimorphotheca ecklonis — Cape marguerite, blue-and-white daisybush (synonym Osteospermum ecklonis )
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Dimorphotheca fruticosa — Trailing African daisy, shrubby daisybush (synonym Osteospermum fruticosum )
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Dimorphotheca jucunda — South African daisy (synonym Osteospermum jucundum )
Distribution
There are about 70 species native to southern and eastern Africa and the Arabian peninsula.
Cultivation
Osteospermum are popular in cultivation, where they are frequently used in summer bedding schemes in parks and gardens. Numerous hybrids and cultivars have been grown with a wide range of tropical colors. Yellow cultivars tend to have a yellow center (sometimes off-white).
Plants prefer a warm and sunny position and rich soil, although they tolerate poor soil, salt or drought well. Modern cultivars flower continuously when watered and fertilised well, and dead-heading is not necessary, because they do not set seed easily.
If planted in a container, soil should be prevented from drying out completely. If they do, the plants will go into "sleep mode" and survive the period of drought, but they will abort their flower buds and not easily come back into flower. Moreover, roots are relatively susceptible to rotting if watered too profusely after the dry period.
Cultivars
Most widely sold cultivars are grown as annuals, are mainly hybrids of O. jucundum, O. ecklonis and O. grandiflorum and can be hardy to -2 °C (30 °F). If hardy, they can be grown as perennials or as shrubs.
Cultivars (those marked agm have gained the Royal Horticultural Society's Award of Garden Merit):
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'Acapulco'
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'African Queen'
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'Apricot'
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'Biera'
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'Big Pink'
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'Blackthorn Seedling' agm
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'Bodegas Pink'
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'Buttermilk' agm
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'Chris Brickell'
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'Duet'
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'Giles Gilbey'
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'Hopleys' agm
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'Ice White'
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'Langtrees agm
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'Lady Leitrim' agm
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'Lilac Spoon'
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'Marbella'
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'Merriments Joy'
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'Nairobi Purple'
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O. jucundum agm
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'Passion Mix'
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'Pink'
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'Pink Beauty'
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'Pink Whirls' agm
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'Silver Sparkler' agm
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'Soprano'
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'Starshine'
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'Springstar Gemma'
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'Sunkist'
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'Weetwood'
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'White Pim' agm
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'White Spoon'
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'White Whirls'
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'Whirlygig'
==Image gallery==
Further reading
External links
