| Brachyscome | |
|---|---|
| Brachycome angustifolia | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Tribe: | Astereae |
| Genus: | Brachyscome |
| Species | |
Brachyscome is a genus of around 70 species of mostly annual and perennial herbs and a few subshrubs in the daisy family Asteraceae. 65 of these are endemic to Australia, the remainder being found in New Zealand and New Guinea. They have typical "daisy" flower heads with showy ray florets in shades of white, pink, mauve, violet or blue, surrounding a usually narrow group of yellow disk florets. The leaves are often dissected to varying degrees but may be linear or spathulate. In growth habit they vary between plants with a rosette of basal leaves and more-or-less leafless flower scape, and those with mostly cauline leaves and often prostrate stems.
The genus is distinguished from other genera in tribe Astereae mainly by the structure of its tiny fruits commonly referred to as "achenes" but more accurately termed cypselas. They are more-or-less club shaped though usually incurved and flattened to varying degrees, and often with a membranous rim or "wing" around the perimeter that is sometimes crenate or ciliate; the pappus is very short, well under 1 mm in length in most species[1].
Brachyscome species are found in a wide range of habitats, though most prolific and diverse on Australia's inland plains, which is where most of the annual species are found. They have also diversified in montane and alpine habitats in south-eastern Australia and New Zealand.
One of the annual plains species, Brachyscome dichromosomatica is remarkable for its extraordinarily low chromosome count. In plants of this species n=2, though some plants have 1, 2 or 3 additional large B chromosomes[2].
Henri Cassini published the genus name Brachyscome in 1816, forming the name from classical Greek brachys, "short" and kome, "hair", referring to the very short pappus hairs. However the combining form of brachys in Greek compound words is brachy- and in a later publication Cassini corrected the spelling to Brachycome. There has been a long-running debate among Australian taxonomists as to whether Cassini's corrected spelling is admissible under the International Code of Botanical Nomenclature, the hardline prioritists insisting on Brachyscome while those favoring stability and adherence to conventional orthography continued until recently to use the spelling Brachycome. A proposal to conserve the genus name with the latter spelling was put forward but rejected in 1993 by the ICBN's Committee for Spermatophyta[3], on the grounds that conservation was unnecessary. This possibly left open the question of whether Brachyscome may be corrected to Brachycome under the orthography clauses of the ICBN. Nowadays all Australian botanical institutions have adopted the spelling Brachyscome.
The species most commonly known to horticulture is Brachyscome iberidifolia, the Swan River Daisy, an annual often sold in seed packets. B. multifida is sold as a rock garden or border plant, as are some hybrid cultivars such as 'Break o' Day' and 'Happy Face'.
Species include: