Banksia marginata

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inflorescence with unopened buds (left), opened flowers (right)


Plant Characteristics
Habit   tree

Height: ⇕ 30 ft"ft" can not be assigned to a declared number type with value 30.
Width: ⇔ 15 ft"ft" can not be assigned to a declared number type with value 15. to 20 ft"ft" can not be assigned to a declared number type with value 20.
Lifespan: ⌛ perennial
Origin: ✈ Australia
Bloom: ❀ late summer, early winter, mid winter, late winter
Cultivation
Exposure: ☼ sun
Water: ◍ moderate, dry
Features: ✓ flowers, foliage, birds, bees, cut flowers
USDA Zones: 8 to 10.5
Flower features: ❀ orange, yellow
Scientific Names

Proteaceae >

Banksia >

marginata >


Banksia marginata, commonly known as the Silver Banksia, is a species of tree or woody shrub in the plant genus Banksia found throughout much of southeastern Australia. Highly variable in form, it can be encountered as a small shrub 20 cm (8 in) high, to a large 12 m (40 ft) tall tree. The narrow leaves are linear and the yellow inflorescences (flower spikes) occur from late summer to early winter. The flower spikes fade to brown and then grey and develop woody follicles bearing the winged seeds.

Many species of bird, in particular honeyeaters, visit the flower spikes, as do native and European honeybees. The response to bushfire varies; some forms are serotinous, that is they are killed by fire and regenerate from large stores of seed which have been held in cones in the plant canopy and are released, while other forms regenerate from underground lignotubers or sucker from lateral roots. Banksia marginata is commonly seen in cultivation, with dwarf forms being registered and sold.

Banksia marginata is a highly variable species, usually ranging from a small shrub around a metre (3 ft) tall to a 12 m (40 ft) high tree.[1] Unusually large trees of 15 to possibly 30 m (50–100 ft) have been reported near Beeac in Victoria's Western District as well as several locations in Tasmania.[2] Conversely, it has been recorded as a compact shrub 20 cm (8 in) high on coastal heathland in Tasmania (such as at Rocky Cape National Park).[3] Shrubs reach only 2 m (7 ft) high in Gibraltar Range National Park.[4] The bark is pale grey and initially smooth before becoming finely tessellated with age. The new branchlets are hairy at first but lose their hairs as they mature,[1] the new growth a pale- or pinkish brown.[5] The leaves are alternately arranged on the stems on 2–5 mm long petioles, and characteristically toothed in juvenile or younger leaves (3 – 7 cm long). The narrow adult leaves are dull green in colour and generally linear, oblong or wedge-shaped (cuneate) and measure 1.5 – 6 cm long and 0.3 – 1.3 cm wide. The margins become entire with age, and the tip is most commonly truncate or emarginate, but can be acute or mucronate.[6] The cellular makeup of the leaves shows evidence of lignification, and the leaves themselves are somewhat stiff.[7] Leaves also have sunken stomates. The leaf undersurface is white with a prominent midrib covered in brownish hairs.[6] The complex flower spikes, known as inflorescences, appear generally from late summer to early winter (February to June) in New South Wales and Victoria, although flowering occurs in late autumn and winter in the Gibraltar Range.[4] Cylindrical in shape, they are composed of a central woody spike or axis from which a large number of compact floral units arise perpendicularly to it and measure 5 – 10 cm tall and 4 – 6 cm wide,[6] Pale yellow in colour, they are composed of up to 1000 individual flowers (784 recorded in the Gibraltar Range[4]) and arise from nodes of branchlets of three years' age or more. Sometimes two may grow from successive nodes in the same flowering season. They can have a grey or golden tinge in late bud. As with most banksias, anthesis is acropetal; the opening of the individual buds proceeds up the flower spike from the base to the top.[6] Over time the flower spikes fade to brown and then grey, and the old flowers generally persist on the cone.[8] The woody follicles grow in the six months after flowering, with up to 150 developing on a single flower spike. In many forms, only a few follicles develop. Small and ellptic, they measure 0.7–1.7 cm long, 0.2–0.5 cm high, and 0.2–0.4 cm wide.[6] In coastal and floodplain forms, these open spontaneously and release seed, while they remain sealed until burnt by fire in plant from heathland and montane habitats. However there are exceptions to each case.[9] Each follicle contains one or two fertile seeds, between which lies a woody dark brown separator of similar shape to the seeds. Measuring 0.9–1.5 cm in length, the seed is egg-to wedge-shaped (obovate-cuneate), and composed of a dark brown 0.8–1.1 cm wide membranous 'wing' and wedge- or sickle-shaped (cuneate-falcate) seed proper which measures 0.5–0.8 cm long by 0.3–0.4 cm wide. The seed surface can be smooth or covered in tiny ridges, and often glistens.[6]

Cultivation

Propagation

Pests and diseases

Varieties

Gallery

References

  1. ↑ 1.0 1.1 Template:Cite encyclopedia
  2. ↑ Liber, Cas (2004). "Really Big Banksias". Banksia Study Group Newsletter 6: 4–5. ISSN 1444–285X. http://anpsa.org.au/banksSG/banksiasg-6-1.pdf. 
  3. ↑ Salkin, p. 145.
  4. ↑ 4.0 4.1 4.2 Vaughton, Glenda; Ramsey, Mike. (2006). "Selfed Seed Set and Inbreeding Depression in Obligate Seeding Populations of Banksia Marginata". Proceedings of the Linnean Society of New South Wales 127: 19–25. ISSN 0370-047X. 
  5. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named George96
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Cite error: Invalid <ref> tag; no text was provided for refs named George 1981
  7. ↑ Read, Jennifer ; Edwards, Cheryl ; Sanson, Gordon D.; Aranwela, Nuvan (2000). "Relationships Between Sclerophylly, Leaf Biomechanical Properties and Leaf Anatomy in Some Australian Heath and Forest Species". Plant Biosystems 134 (3): 261–77. doi:10.1080/11263500012331350445. 
  8. ↑ Holliday, Ivan; Watton, Geoffrey (2008) [1977]. Banksias: A Field and Garden Guide (3rd ed.). Adelaide, South Australia: Australian Plants Society (SA Region). pp. 100–01. ISBN 0-9803013-1-1. 
  9. ↑ Salkin, p. 146.

External links


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