Bottlebrush2

Plant species: //Callistemon citrinus// Plant family: Myrtaceae Common name: Red bottlebrush Distribution: Temperate regions around the East and South-East coast of Australia, favouring slightly more moist soil. Habit: A large shrub up to 3 metres tall. A common plant roadside in nature strips. Inflorescence: Approximately 7cm long. Flowers line the sides of the inflorescence and it terminates with a few leaves at the end. Flowers: Clusters of long red stamens arranged in a similar fashion to a circular dishwashing brush. Fruit: Hard, woody pods approximately 5mm in diameter.



Verbal description of plant morphology
Several red masses stick out along one inflorescence, with a few small leaves at the end. The largest and most striking feature are the stamens, which are numerous, red coloured and have a dark brown capsule of pollen at the end. Each flower has a single anther in the centre, which are slightly longer and thicker than the stamens and have a white capsule at the end. At the base of the flower exist small, thick petals (slightly yellow/white) and sepals (green) which house and protect the ovule. After fertilisation most of the flower dries and falls off, except the ovule and its covering, which becomes a hard woody coat to protect the seed. Given the toughness of this woody coat, it is possible that the seeds are released during bushfire.

Variability of plant morphology
Measurements were made using vernier callipers for small lengths, and rulers for lengths larger than 10cm. All measurements are in millimetres and are to the nearest millimetre.
 * Flower number || Sepal length || Anther length || Distance between seed cases along inflorescence || Length of inflorescence (betweeen most extreme seed cases) || Width of seed coat ||
 * Flower 1 || 27 || 19 || 3 || 74 || 5 ||
 * Flower 2 || 21 || 18 || 2 || 65 || 5 ||
 * Flower 3 || 24 || 19 || 3 || 84 || 5 ||
 * Average || 24 || 18.667 || 2.667 || 87.333 || 5 ||
 * Standard deviation || 3 || 0.577 || 0.577 || 9.504 || 0 ||

Pollen information
The pollen grains of this species have a trigonal shape. The abundance of pollen grains appears to be much less than other species. However this may simply be a sampling bias caused by selection of a young flower, or it could be casued by the pollen grains being relatively difficult to dislodge, which isn't unreasonable considering the close proximity of the anther to the stamens.