Callistemon

Bottlebrushes
File:Red bottle brush.jpg
Red bottlebrush flower
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Myrtales
Family:	Myrtaceae
Subfamily:	Myrtoideae
Tribe:	Melaleuceae
Genus:	Callistemon R.Br.

Callistemon /ˌkælᵻˈstiːmən/ is a genus of shrubs in the family Myrtaceae, first described as a genus in 1814. The entire genus is endemic to Australia but widely cultivated in many other regions and naturalized in scattered locations. Their status as a separate taxon is in doubt, some authorities accepting that the difference between callistemons and melaleucas is not sufficient for them to be grouped in a separate genus.

Description

Callistemon species have commonly been referred to as bottlebrushes because of their cylindrical, brush like flowers resembling a traditional bottle brush. They are mostly found in the more temperate regions of Australia, especially along the east coast and typically favour moist conditions so when planted in gardens thrive on regular watering. However, two species are found in Tasmania and several others in the south-west of Western Australia. At least some species are drought-resistant and some are used in ornamental landscaping elsewhere in the world.

File:Bottlebrush seeds.jpg

Bottlebrush seed capsules

File:Bottlebrush03.jpg

Callistemon citrinus

File:Callistemon pallidus1.jpg

Callistemon pallidus

File:Callistemon.jpg

Callistemon viminalis

File:C viminalis3.jpg

Callistemon viminalis

Taxonomy

The genus Callistemon was first formally described in 1814 by Robert Brown. In his description he noted that the genus includes “those species of Metrosideros that have inflorescence similar to that of Melaleuca, and distinct elongated filaments.” Carl Linnaeus had described the genus ‘’Melaleuca’’ in 1767 and in 1867, George Bentham brought all the Metrosideros species into Melaleuca. Bentham described melaleucas as having stamens united in bundles opposite the (five) petals.

In his 1864 description of Callistemon salignus in Fragmenta phytographiae Australiae, Ferdinand von Mueller noted that the difference between the genera was “entirely artificial” (“omnino artificiale"). George Bentham also noted in ‘’Flora Australiensis’’ that Callistemon “passes gradually into Melaleuca, with which F. Mueller proposes to unite it.” In 1876, Henri Ernest Baillon proposed in Histoire des Plantes that Callistemon, as well as Calothamnus and Lamarchea be merged into Melaleuca.

Nevertheless, most authors had preserved the distinction between the two genera ‘’Callistemon’’ and ‘’Melaleuca’’ until 1998. In that year, in recognition of the fact that the callistemons and melaleucas on New Caledonia were clearly related, Lyndley Craven and J.W. Dawson transferred the callistemons on that island to ‘’Melaleuca’’, even though some (eg. Melaleuca pancheri) do not have stamens fused in 5 groups.

On the basis of DNA evidence, in 2006 and 2009 Craven moved all but four callistemons to melaleuca. Those four were Callistemon forresterae, Callistemon genofluvialis, Callistemon kenmorrisonii and Callistemon nyallingensis which were regarded as being hybrids.

The new description of ‘’Melaleuca’’ has been accepted by some herbaria but not all. For example, the Queensland Herbarium accepts Melaleuca flammea (synonym Callistemon acuminatus) but the New South Wales Herbarium accepts Callistemon acuminatus. In 2012, Frank Udovicic and Roger Spencer transferred the newly described species of melaleuca with separate stamens (eg. Melaleuca megalongensis and Melaleuca wimmerensis) to Callistemon (hence Callistemon melalongensis and Callistemon wimmerensis). Their argument is that using the DNA evidence is premature. They further argue that if all the genera Beaufortia, Callistemon, Calothamnus, Conothamnus, Eremaea, Melaleuca, Phymatocarpus were combined (as Craven has suggested), then there would be no characteristics that would define the group.

Use in horticulture

Many commercial nurseries continue to use the name ‘’Callistemon’’. These species can be propagated either by cuttings (some species more easily than others), or from the seeds. Flowering is normally in spring and early summer (October–December), but conditions may cause flowering at other times of the year. The obvious parts of the flower masses are stamens, with the pollen at the tip of the filament; the petals are inconspicuous (see picture). Flower heads vary in colour with species; most are red, but some are yellow, green, orange or white. Each flower head produces a profusion of triple-celled seed capsules around a stem (see picture) which remain on the plant with the seeds enclosed until stimulated to open when the plant dies or fire causes the release of the seeds. A few species release the seeds annually.

Bottlebrush plants can be grown in pots.

They have been grown in Europe since a specimen of Callistemon citrinus was introduced to Kew Gardens in London by Joseph Banks in 1789.

Species

One of the sources was the Kew World Checklist of Selected Plant Families.

1. Callistemon acuminatus Cheel – Tapering-leaved Bottlebrush
2. Callistemon brachyandrus Lindl. – Prickly Bottlebrush
3. Callistemon chisholmii Cheel
4. Callistemon citrinus (Curtis) Skeels – Lemon Scented Bottle Brush
5. Callistemon coccineus F.Muell.
6. Callistemon comboynensis Cheel – Cliff Bottlebrush
7. Callistemon flavovirens (Cheel) Cheel – Green Bottlebrush
8. Callistemon formosus S.T.Blake
9. Callistemon forresterae Molyneux
10. Callistemon genofluvialis Molyneux
11. Callistemon glaucus (DC.) Sweet
12. Callistemon hemistictus (S.T.Blake ex Craven) Udovicic and R.D.Spencer
13. Callistemon kenmorrisonii Molyneux – Betka Bottlebrush
14. Callistemon lanceolatus (Sm.) Sweet
15. Callistemon lazaridis (Craven) Udovicic & R.D.Spencer
16. Callistemon linearifolius (Link) DC.
17. Callistemon linearis Sweet
18. Callistemon macropunctatus (Dum.Cours.) Court
19. Callistemon megalongensis (Craven & S.M.Douglas) Udovicic & R.D.Spencer
20. Callistemon montanus C.T.White ex S.T.Blake – Mountain Bottlebrush
21. Callistemon montis-zamiae (Craven) Udovicic & R.D.Spencer
22. Callistemon nervosus Lindl.
23. Callistemon nyallingensis Molyneux
24. Callistemon pachyphyllus Cheel – Wallum Bottlebrush
25. Callistemon pallidus (Bonpl.) DC. – Lemon Bottlebrush
26. Callistemon paludosus F.Muell.
27. Callistemon pauciflorus R.D.Spencer & Lumley
28. Callistemon pearsonii R.D.Spencer & Lumley
29. Callistemon phoeniceus Lindl. – Lesser Bottlebrush
30. Callistemon phratra (Craven) Udovicic & R.D.Spencer
31. Callistemon pinifolius (Wendl.) Sweet – Pine-leaved Bottlebrush
32. Callistemon pityoides F.Muell. – Alpine Bottlebrush
33. Callistemon polandii F.M.Bailey
34. Callistemon pungens Lumley & R.D.Spencer
35. Callistemon pyramidalis (Craven) Udovicic & R.D.Spencer
36. Callistemon quercinus (Craven) Udovicic & R.D.Spencer
37. Callistemon recurvus R.D.Spencer & Lumley
38. Callistemon rigidus R.Br. – Stiff Bottlebrush
39. Callistemon rugulosus (Schltdl. ex Link) DC. – Scarlet Bottlebrush
40. Callistemon sabrina (Craven) Udovicic & R.D.Spencer
41. Callistemon salignus (Sm.) Sweet – Willow Bottlebrush, White Bottlebrush
42. Callistemon serpentinus (Craven) Udovicic & R.D.Spencer
43. Callistemon shiressii Blakely
44. Callistemon sieberi DC.
45. Callistemon speciosus (Sims) Sweet
46. Callistemon subulatus Cheel
47. Callistemon teretifolius F.Muell. – Needle Bottlebrush, Flinders Ranges Bottlebrush
48. Callistemon viminalis (Sol. ex Gaertn.) G.Don – Weeping Bottlebrush
49. Callistemon viridiflorus (Sims) Sweet
50. Callistemon wimmerensis Marriott & G.W.Carr

Gallery

• Bottlebrush (Callistemon) bud.jpg

  Foreground: Bottlebrush buds. Background: Partial blooming bottlebrush flower.

• Blooming bottlebrush (Callistemon) found in Kelantan, Malaysia.JPG

  Blooming bottlebrush found in Kelantan, Malaysia.

• Bottlebrush (Callistemon).jpg

  Bottlebrush flower partial blooming found in Kelantan, Malaysia.

• Red bottlebrush tree in Florida crop.jpg

  Tree in bloom in Florida.

• 

  Illustration showing bottle brushes, the namesake of the plant

See also

• List of Callistemon cultivars

External links

• The Callistemon Page
• Australian National Botanic Gardens: Callistemon (Bottlebrushes)

• Sunset Western Garden Book, 1995:606–607
• Brown, Robert. 1814. Voyage to Terra Australis 2(App. 3): 547
• Kew World Checklist of Selected Plant Families