Bottlebrush+Callistemon


 * Group members: Aladdin, Lindsay, Greg, Kylie, Katie**


 * Plant species: **// Callistemon citrinus //

__Plant family:__ Myrtacaea __Common name__: Crimson bottlebrush

__Habitat:__ Woody shrubs ranging from 0.5m in height to 4m - the shrub contains many influorescences that are made up of individual flowers

__Distribution:__ Bottlebrushes are mostly found in the east and south-east of Australia however some are also found in Western Australia and New Caledonia. They usually grow in areas subject to dampness or flooding, such as along creeks.



__Source:__ Australian National Herbarium, http://www.anbg.gov.au/callistemon/index.html


 * Figure 1: ** Large Crimson Bottlebrush inflorescence (approximately 10-15cm in length).

__ Pollination and Fertilisation __
 * Bottlebrush displays inflorescences composed of many bright red flowers which are grouped together. The larger group of flowers make it extremely attractive to birds, which have good eyesight and are very sensitive to the colour red. The infloresences are also found at the apex of branches, making them more accessible for birds. This also prevents mammals such as possums from pollinating it as the flowers have no odour and are placed on weak branches.
 * __Pollination process__: birds will come for nectar, touch anther of flower in the process. Bird flies away with pollen on it. It delivers this pollen onto the stigma of another flower and fertilisation will occur
 * Bees cannot see red light - therefore not bee pollinated: lack of UV markings support this
 * Some small insects like ants were observed climbing in between the stamens to reach the nectar without pollinating the plant.

**Figure 2**: Crimson Bottlebrush flower: small with dense groupings of bright crimson filaments. The style is longer than the stamen to prevent self- pollination.

__Fruit__: Small, woody and abundant, forming in clusters along the stem - NB: some bottlebrushes rely on fire to open their fruits for seed dispersal.

__Seed__: Small, woody, brown, very abundant.

**Floral Morphology**
 * Figure 3:** Schematic diagram of various floral structures found in the Crimson Bottlebrush.

__Source:__ Australian National Herbarium, http://www.anbg.gov.au/callistemon/index.html


 * Table 1:** Various lengths of the structural components of the flower in Crimson Bottlebrush.
 * ** Flower ** ||  ** Colour **  ||  ** Flower Appearance **  ||  ** Length (mm) **  ||  ** Style Length (mm) **  ||  ** Stamen Length (mm) **  ||
 * 1 ||  Red  ||  Elongated with a great abundance of filaments growing vertically from the calyx lobe  ||  31.30  ||  30.00  ||  22.35  ||
 * 2 ||  Red  ||  ‘’  ||  30.50  ||  29.70  ||  16.00  ||
 * 3 ||  Red  ||  ‘’  ||  33.10  ||  26.00  ||  19.00  ||
 * 4 ||  Red  ||  ‘’  ||  29.51  ||  28.00  ||  25.90  ||
 * 5 ||  Red  ||  ‘’  ||  29.30  ||  30.60  ||  25.75  ||
 * ** Average ** ||   ||   ||  30.74  ||  28.58  ||  21.80  ||
 * ** SD ** ||   ||   ||  1.38  ||  16.2  ||  3.85  ||

The flowers contain both male and female parts, and pollen was only produced in the younger flowers at the branch apex. The anthers and filaments may mature at different rates, and along with self incompatibility, this can further prevent self fertilisation.

The petals have become greatly reduced in size, and the red filaments of the stamen have become the main attractant feature of the flower. The filaments are densely spaced and may act to prevent medium - large insects from taking nectar without pollinating the plant.


 * Pollen Morphology**


 * Figure 4:** Crimson bottlebrush pollen viewed at 100X magnification.

Football-shaped stamens are very abundant. However, pollen which is triangular shaped is not extremely plentiful. This has ramifications for how the plant is pollinated. Wind pollination is not possible due to the limited amount of pollen and the stickiness of the anther which reduces the ability for dispersal. However, the abundance of inflorescence on trees and the high number of flowers on each inflorescence means the plant is not only visible but attractive to birds, specifically small birds due to the strength of the branches.


 * Nectar Morphology**

Nectar concentration was quite high (20.7% Brix) and a large amount of nectar was present.