Xerochrysum bracteatum

French botanist Étienne Pierre Ventenat described the golden everlasting as Xeranthemum bracteatum in his 1803 work Jardin de Malmaison, a book commissioned by Napoleon's first wife Joséphine de Beauharnais to catalogue rare plants that she had collected and grown at the Château de Malmaison. The Latin species name bracteatum refers to the papery bracts (often mistakenly called petals) of the flower heads. Henry Cranke Andrews transferred it to the genus Helichrysum based on the morphology of its receptacle in 1805, and it was known as Helichrysum bracteatum for many years. Leo Henckel von Donnersmarck described it as Helichrysum lucidum in 1806, and Christiaan Hendrik Persoon as Helichrysum chrysanthum in 1807. It was given the name Bracteantha bracteata in 1991, when Arne Anderberg and Laurie Haegi placed the members that are known as strawflowers of the large genus Helichrysum into a new genus Bracteantha, and designated B. bracteata as the type species. However, they were unaware that Russian botanist Nikolai Tzvelev had already placed X. bracteatum in the new, and at the time monotypic, genus Xerochrysum the previous year. This name was derived from the Greek words "dry", and "golden", likely relating to the nature of the distinctive bracts. Confusion existed for a decade, with Bracteantha appearing in literature and the horticultural trade until it was clarified in 2002 that the latter name took precedence. X. bracteatum itself is very variable and may represent several cryptic species. Xerochrysum bracteatum and its relatives belong to the Gnaphalieae or paper daisies, a large tribe within the daisy family, Asteraceae. However, a 2002 molecular study of the Gnaphalieae has indicated the genus Xerochrysum is probably polyphyletic, as the two species sampled, X. bracteatum and X. viscosum, were not closely related to each other. X. bracteatum has been recorded hybridising with X. viscosum and X. papillosum in cultivation, and possibly also Coronidium elatum and C. boormanii. ==Description==

The plant is an erect perennial, or occasionally annual, herb that is simple or rarely branched at its base. It generally reaches in height, but can have a prostrate habit in exposed areas such as coastal cliffs. The green stems are rough and covered with fine hairs, and are robust compared with those of other members of the genus. The leaves are lanceolate, elliptic, or oblanceolate in shape and measure long and from wide. They are also covered with cobwebby hairs. Sitting atop tall stems above the foliage, the flower heads range from in diameter. Occasionally, multiple heads arise from the one stem. They create the impression of a shiny and yellow corolla around the disc. The intermediate bracts are sometimes white, while the outer ones are paler and often streaked reddish or brown (a greater variety of colours are found in cultivars). The individual florets are yellow. Yellow in colour, they persist and are thought to aid in the wind dispersal of the long fruit. The smooth brown fruit, known as a cypsela, is 2 to 3 mm long with the pappus radiating from one end. The eastern Australian species X. viscosum may be distinguished by its rough and sticky leaves. The plant is a source of helenynolic acid, a rare fatty acid. ==Distribution and habitat==

Xerochrysum bracteatum occurs in all Australian mainland states and territories, as well as Tasmania. Widespread, it is found from North Queensland across to Western Australia, and in all habitats excluding densely shaded areas. responding rapidly to bouts of rainfall to complete its lifecycle. It is common among granite outcrops in southwest Western Australia, It has been reported growing in disturbed soil, along roadsides and in fields in the New England region in the United States. ==Ecology==

The brightly coloured bracts act as petals to attract insects such as hoverflies, native bees, and small beetles that pollinate the florets. The caterpillars of Tebenna micalis have been recorded on this species, as have those of the Australian painted lady (Vanessa kershawi). The tiny fruits are dispersed by wind, and germinate and grow after fire or on disturbed ground. The water mould (oomycete) Bremia lactucae has infected commercial crops in Italy and California. In 2002 on the Ligurian coast, widespread infection of several cultivars, most severely 'Florabella Pink' and to a lesser extent 'Florabella Gold' and 'Florabella White', resulted in leaf blistering and the development of chlorotic lesions on the leaves, and white patches on the undersides, particularly in areas of poor ventilation. There was an outbreak of downy mildew in a cultivated crop of Xerochrysum bracteatum in San Mateo County, California in 2006, in which the leaves developed large chlorotic lesions. A Phytoplasma infection damaged X. bracteatum crops in the Czech Republic between 1994 and 2001, causing poor growth, bronzing of foliage, and malformation of flower heads. Genetically, the pathogen was indistinguishable from the agent of aster yellows. The root-knot nematode (Meloidogyne incognita) attacks and forms galls on the roots, which leads to the morbidity or death of the plant. ==Cultivation==

Xerochrysum bracteatum had been introduced to cultivation in England by 1791. German horticulturist Herren Ebritsch obtained material and developed it at his nursery in Arnstadt near Erfurt in Germany. He bred and sold cultivars of many colours from bronze to white to purple, which spread across Europe in the 1850s. The bracts of these early forms tended to remain cupped around the flower head rather than flatten out like the native Australian forms. Some coloured forms of South African Helichrysum are thought to have been introduced to the breeding program, which resulted in the huge array of colours. X. bracteatum was one of several species that became popular with European royalty and nobility from the early 19th century, yet were little noticed in Australia until the 1860s, when they became more prominent in Australian gardens. 'Dargan Hill Monarch' was the first of these, and many more have followed. Queensland-based company Aussie Winners has a range of compact plants ranging from orange to white known as Sundaze. Plants of this series usually have larger leaves. This range won the ''Gran premio d'oro'' at the Euroflora exposition in Geneva in 2001, for the best new plant series in the previous three years. 'Florabella Gold', a member of the Florabella series, won the award for best new pot plant (vegetative) in the Society of American Florists' competition of 1999. Other commercial ranges include the Nullarbor series, and Queensland Federation daisies, including 'Wanetta Sunshine' and 'Golden Nuggets'. Xerochrysum bracteatum can be grown in large pots or window boxes, and is a good pioneer plant in the garden until other plants become more established. Lower-growing cultivars are suitable for hanging baskets and border plantings. Dried flowers are long lasting—up to some years—and are used in floral arrangements and the cut flower industry. The main factor limiting lifespan of dried flowers is the wilting of stems, so flowers are sometimes wired into arrangements. Immersing flowers in glycerol or polyethylene glycol also lengthens lifespan. Cultivars • 'Bright Bikini' has gained the Royal Horticultural Society's Award of Garden Merit. • 'Dargan Hill Monarch' was a natural form collected around inland from Cunninghams Gap in southern Queensland in May 1961, and registered in February 1977. It is a low perennial shrub high and across. The foliage is grey and the large flowers are 7–9 cm in diameter and golden yellow in colour. It grows best in full sun and fair drainage. Cuttings strike readily, as does seed, although seedlings may differ from the parent. • 'Golden Bowerbird' is a hybrid, bred by a deliberate backcross of 'Cockatoo' to 'Dargan Hill Monarch' by Doug McKenzie, who applied for registration with the ACRA in 1980. (It was granted in 1981.) It has much larger flower heads than both parents, yet is a smaller shrub, which reaches high by wide. Denser than that of other forms, the foliage is covered in fine grey hair. On stalks around above the foliage, the flower heads measure up to in diameter, although larger ones up to 10 cm are occasionally seen. They have around 300 bracts per flower head, compared with 80 for 'Dargan Hill Monarch' and 200 in 'Cockatoo', giving them a "doubled" look. It is reported as producing fewer flower heads than 'Princess of Wales'. • 'Princess of Wales' is a spontaneous hybrid, arising from a cross between 'Dargan Hill Monarch' and an annual form. Arising in the Australian National Botanic Gardens in Canberra, it was selected by employee Peter Ollerenshaw in summer 1983. He applied to register the cultivar with ACRA in March 1985. The flower heads are golden yellow and measure across. It makes an ideal plant for rockeries, and strikes easily from cuttings during the spring growing period. • 'Hastings Gold' was a natural form from Hastings Point to the east of Murwillumbah on the New South Wales far north coast. It is a perennial herb with green bushy foliage reaching high and wide. The golden yellow flower heads measure across and are held on stalks above the foliage. It is smaller than the similarly coloured 'Dargan Hill Monarch' and larger than 'Diamond Head'. • 'Nullarbor Flame' was a selection introduced into cultivation in 1997 that produces abundant red flowers with yellow discs and a diameter of . The plant grows to tall and wide. • 'Pink Sunrise' was developed by Goldup Nurseries in Victoria in 1986, of unknown origin, presumably a hybrid. It is a compact perennial that reaches high and wide. The flower heads are pink in bud, before opening as cream with orange discs. • 'White Monarch' was a spontaneous garden hybrid that resembles 'Dargan Hill Monarch' but with white flower heads with orange discs measuring up to in diameter. • 'Lemon Monarch' resembles 'Cockatoo', but its lemon-coloured flower heads have fewer bracts. • 'Strawburst Yellow', patented as 'Stabur Yel', is a form with large bright yellow flower heads averaging around in diameter. The result of a planned breeding program in Gilroy, California, it was bred by Jason Jandrew of Goldsmith Seeds from a lemon yellow-flowered form crossed with a yellow-flowered form in 2005. The pollination occurred in May, the resultant seed was sown in September, and what was to become the clone was chosen in December for its large flower size, colour and compact foliage. • 'Lemon Princess' is thought to be a hybrid between X. bracteatum and X. viscosum. ==References==