Pycnosorus

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Pycnosorus
Pycnosorus globosus flowerhead1 (17796565360).jpg
Pycnosorus globosus
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Subfamily: Asteroideae
Tribe: Gnaphalieae
Genus: Pycnosorus
Benth. [1]

Pycnosorus is a genus of six species of plants in the family Asteraceae. Commonly known as billy buttons or drumsticks, they are annual or perennial herbs or small shrubs with a cylindrical to spherical head of up to 200 daisy-like "flowers". Each "flower" is a pseudanthium consisting of between three and eight florets surrounded by bracts. The petals are joined to form a small tube and the florets with their surrounding bracts are yellow or golden-yellow.

Contents

Description

Plants in the genus Pycnosorus are annual or perennial herbs, with leaves decreasing in size up the stem, those at the base withering first. The flowers are arranged in oval to more or less spherical heads of 40 to 200 flower-like partial heads. Each partial head consists of three to eight small flower-like "florets". The florets and the bracts which surround them are yellow or golden in colour. Each flower has five petals joined to form a tube. After pollination the flowers become silky achenes with a ring of feathery bristles. [2] [3]

Plants in the closely related genus Craspedia are also known by the common name "billy buttons" but have their flowers on small stalks rather than attached directly to the receptacle ("sessile") as in Pycnosorus. [4] [2] There is some evidence that the two genera may in fact be monophyletic. [5]

Taxonomy and naming

The genus was first formally described in 1837 by George Bentham and the description was published in Enumeratio plantarum quas in Novae Hollandiæ ora austro-occidentali ad fluvium Cygnorum et in sinu Regis Georgii collegit Carolus Liber Baro de Hügel . [6] Bentham nominated Pycnosorus globosus as the type species. [7] The genus name (Pycnosaurus) is derived from the Ancient Greek words pyknos meaning "dense" or "thick" [8] :644 and soros meaning "heap". [8] :728

The following is a list of species of Pycnosorus accepted by the Australian Plant Census as at 30 November 2019:

Distribution and habitat

All six species of Pycnosorus are endemic to Australia and there are species in all states except Tasmania. Most species grow in heavy, often rocky soils. [2]

Related Research Articles

<i>Hardenbergia</i> Genus of legumes

Hardenbergia is a genus of three species of flowering plants in the pea family, Fabaceae and is endemic to Australia. Plants in this genus are climbing or trailing herbs or subshrubs with pinnate leaves with one, three or five leaflets and groups of violet, white or pinkish flowers in pairs or small clusters in leaf axils. Species of Hardenbergia occur in all Australian states and in the Australian Capital Territory.

<i>Chorilaena</i> Genus of flowering plants

Chorilaena quercifolia, commonly known as karri oak or chorilaena, is a species of bushy shrub that is endemic to the karri forests of south-west Western Australia. It is the sole species in the genus Chorilaena. It has papery, broadly egg-shaped leaves with lobed edges and variously-coloured flowers arranged in umbels of five, the sepals and petals hairy on the outside and the stamens protruding beyond the petals.

<i>Darwinia citriodora</i> Species of flowering plant

Darwinia citriodora, commonly known as lemon-scented darwinia or lemon scented myrtle, is a plant in the myrtle family Myrtaceae and is endemic to the south-west of Western Australia. It is a shrub with oblong to lance-shaped leaves and red, yellow and orange flowers over an extended period. It is a hardy plant in well-drained soil, is often cultivated and used as a rootstock for less hardy species.

<i>Ixiolaena</i> Genus of flowering plants

Ixiolaena is a genus of flowering plants in the daisy family.

<i>Pomaderris ferruginea</i> Species of shrub

Pomaderris ferruginea, commonly known as rusty pomaderris, is a species of flowering plant in the family Rhamnaceae and is endemic to south-eastern continental Australia. It is a shrub with rusty-hairy stems, egg-shaped leaves, and clusters of cream-coloured, whitish or yellow flowers.

Camptacra gracilis is a species of flowering plants in the family Asteraceae. It is native to northern Australia, and to the island of New Guinea.

<i>Myoporum caprarioides</i> Species of shrub

Myoporum caprarioides, commonly known as slender myoporum, is a plant in the figwort family, Scrophulariaceae. It is a shrub with wart-like tubercles covering its branches and leaves, especially on the upper surface and white flowers spotted with mauve, or all blue-mauve, present for most of the warmer months.

<i>Bossiaea eriocarpa</i> Species of legume

Bossiaea eriocarpa, commonly known as common brown pea, is a species of flowering plant in the family Fabaceae and is endemic to the south-west of Western Australia. It is a shrub with narrow oblong or linear leaves and yellow and red flowers.

<i>Olearia ciliata</i> Species of shrub

Olearia ciliata, commonly known as the fringed daisy bush, is a small shrub with large clusters of bright purple-blue flowers on a single stem.

<i>Scaevola pilosa</i> Species of flowering plant

Scaevola pilosa, commonly known as the hairy fan-flower, is a perennial herb in the family Goodeniaceae. It is endemic to the southwest of Western Australia.

Hemiandra linearis, commonly known as speckled snakebush, is a species of prostrate to ascending shrub that is endemic to the south-west of Western Australia.

<i>Comesperma integerrimum</i> Species of plant

Comesperma integerrimum is a twining shrub or climber in the family Polygalaceae.

<i>Goodenia fasciculata</i> Species of plant

Goodenia fasciculata is a species of flowering plant in the family Goodeniaceae and is endemic to the south-west of Western Australia. It an ascending shrub with bunched, narrow linear stem leaves and spikes of white flowers.

<i>Goodenia pulchella</i> Species of plant

Goodenia pulchella is a species of flowering plant in the family Goodeniaceae and is endemic to the south-west of Western Australia. It is an erect to ascending herb with lance-shaped leaves mostly at the base of the plant, and racemes of yellow flowers.

<i>Gompholobium aristatum</i> Species of flowering plant

Gompholobium aristatum is a species of flowering plant in the family Fabaceae and is endemic to the south-west of Western Australia. It an erect shrub that typically grows to a height of 10–80 cm (3.9–31.5 in). It flowers between July and December producing yellow, pea-like flowers. This species was first formally described in 1837 by George Bentham in Stephan Endlicher's Enumeratio plantarum quas in Novae Hollandiae ora austro-occidentali ad fluvium Cygnorum et in sinu Regis Georgii collegit Carolus Liber Baro de Hügel from specimens collected in the Swan River Colony. The specific epithet (aristatum) means "awned", referring to the leaves.

<i>Hibbertia perfoliata</i> Species of flowering plant

Hibbertia perfoliata is a species of flowering plant in the family Dilleniaceae and is endemic to Western Australia. It is a weak, ascending or prostrate, spreading shrub that typically grows to a height of up to 40 cm (16 in). It flowers from September to December or from January to March and has yellow flowers. The species was first formally described in 1837 by Stephan Endlicher from an unpublished description by Charles von Hügel and Endlicher's description was published in his book Enumeratio plantarum quas in Novae Hollandiae ora austro-occidentali ad fluvium Cygnorum et in sinu Regis Georgii collegit Carolus Liber Baro de Hügel. The specific epithet (perfoliata) means "perfoliate".

<i>Hibbertia racemosa</i> Species of flowering plant

Hibbertia racemosa, commonly known as stalked guinea flower, is a species of flowering plant in the family Dilleniaceae and is endemic to the south-west of Western Australia. It is an erect or ascending, spreading shrub that typically grows to a height of 10–75 cm (3.9–29.5 in) and produces yellow flowers between July and December.

<i>Kennedia carinata</i> Species of legume

Kennedia carinata is a species of flowering plant in the family Fabaceae and is endemic to the south-west of Western Australia. It is a prostrate shrub with trifoliate leaves and reddish-purple, pea-like flowers.

<i>Lechenaultia floribunda</i> Species of flowering plant

Lechenaultia floribunda, commonly known as free-flowering leschenaultia, is a species of flowering plant in the family Goodeniaceae and is endemic to the south-west of Western Australia. It is an openly-branched shrub or subshrub with crowded, narrow, fleshy leaves and compact groups of pale blue to pale mauve or creamy white flowers.

Lasiopetalum cordifolium, is a species of flowering plant in the family Malvaceae and is endemic to the south-west of Western Australia. It is an erect shrub with hairy stems, heart-shaped leaves and pink, cream-coloured or white flowers.

References

  1. "Pycnosorus". Australian Plant Census. Retrieved 10 December 2019.
  2. 1 2 3 Doust, Andrew N.; Everett, Joy. "Pycnosorus". Royal Botanic Garden Sydney. Retrieved 27 October 2018.
  3. Everett, Joy; Doust, Andrew (1992). "New species and a new combination in Pycnosorus (Asteraceae:Gnaphalieae)". Telopea. 5 (1): 39–43. doi: 10.7751/telopea19924959 . Retrieved 27 October 2018.
  4. Everett, Joy; Doust, Andrew N. "Genus Craspedia" . Retrieved 14 February 2019.
  5. Schmidt-Lebuhn, Alexander N. (2013). "Reciprocal monophyly of Craspedia and Pycnosorus (Asteraceae, Gnaphalieae) and the problems of using ribosomal DNA at the lowest taxonomic levels". Australian Systematic Botany . 26 (3): 233. doi:10.1071/SB13018.
  6. Tropicos, Pycnosorus Benth.
  7. George Bentham (1837). Stephen Endlicher (ed.). Enumeratio plantarum quas in Novae Hollandiae ora austro-occidentali ad fluvium Cygnorum et in Sinu Regis Georgii collegit Carolus liber baro de Hügel. London. Retrieved 17 November 2017.
  8. 1 2 Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.