Pycnosorus

Billy buttons
Pycnosorus globosus
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Gnaphalieae[1]
Genus: Pycnosorus

Pycnosorus is a genus of six species of plants in the daisy 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.[2][3]

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 .[4] Bentham nominated Pycnosorus globosus as the type species.[5] The genus name (Pycnosaurus) is derived from the Ancient Greek words pyknos meaning "dense" or "thick" [6]:644 and soros meaning "heap".[6]:728

Species[1][7][8]
  • Pycnosorus chrysanthes (Schldl.) Sond. – golden billy-buttons
  • Pycnosorus eremaeus J.Everett & Doust
  • Pycnosorus globosus (F.Muell.) Benth – drumsticks
  • Pycnosorus melleus J.Everett & Doust
  • Pycnosorus pleiocephalus (F.Muell.) J.Everett & Doust – soft billy-buttons
  • Pycnosorus thompsonianus J.Everett & Doust

Distribution and habitat

All six species of Pycnosorus are endemic to Australia and grow in a wide range of habitats from sea level to the alps. The genus is found in every state of Australia, except Western Australia.[3]

Use in horticulture

Pycnosorus globosa is a commonly grown cut flower, and is exported to the world from wild collection from around the Murray River. The tall flower stalks, with their yellow spikey spherical heads are very popular, particularly in Japan. Pycnosorus can be propagated by division by cutting a rosette from a clump or by seed. Seeds from temperate varieties will germinate in days if lightly sprinkled on seed raising media and not covered. Plants are generally only poorly self-fertile. In the wild they grow in very poor soils that are seasonally inundated. In cultivation they appreciate good potting mix, including phosphorus. Most species are widely grown both as ornamentals and for revegetation work.

See also

A closely related genus is Craspedia. One way to distinguish these genera is to note whether the individual flowers are directly attached to the flower base (Pycnosorus) or are attached via little stalks (Craspedia) .

References

  1. 1 2 Flann, C (ed) 2009+ Global Compositae Checklist Archived 2015-01-03 at Archive.is
  2. ↑ Doust, Andrew A. N. L.; Everett, Joy. "Pycnosorus". Royal Botanic Garden Sydney. Retrieved 17 November 2017.
  3. 1 2 Everett, Joy; Doust, Andrew A. N. L. (1992). "New species and a new combination in Pycnosorus (Asteraceae:Gnaphalieae)". Telopea. 5 (1): 39–43. Retrieved 17 November 2017.
  4. ↑ Tropicos, Pycnosorus Benth.
  5. ↑ Bentham, George; Endlicher, Stephan (ed.) (1837). 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.
  6. 1 2 Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
  7. ↑ "Pycnosorus". Australian Plant Name Index (APNI), IBIS database. Centre for Plant Biodiversity Research, Australian Government, Canberra. Retrieved 2009-02-07.
  8. ↑ Atlas of Living Australia
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