Ozothamnus diosmifolius

A shrub that will reach a height of potentially 5 metres with a spread to possibly 2 metres. It is often seen in the field to 2 metres tall by less than 1 metre wide.

It is a very commonly seen species in many habitats, with a large natural geographic range in NSW, gorwing along the entirety of the coast and tablelands areas, as well as the north and central western plains, extending just into the far western plains. It has been recorded in the far north-east corner of Victoria. It extends into Queensland, growing as far north as around Bundaberg and west of here towards Tambo.

It is often found in wet and dry sclerophyll woodland and forest as well as rainforest edges and shrubland, on a variety of soils but often heavier, i.e. clays, alluvium and volcanic.

Ozothamnus spp. have simple and alternate/clustered leaves. In this species, they are dark to mid green, linear to narrowly-elliptic, to about 15 mm long by 2 mm wide, with margins strongly curled under and with the lower surface covered in white woolly hairs. Leaves are somewhat aromatic and rough to the touch due to short hairs on the upper surface.

Ozothamnus are in the daisy family (the world’s largest family of species) which means their flowers are arranged in a capitulum or ‘daisy head’. Daisies are somewhat unique in that they have evolved inflorescences that appear to look like one flower. The Sunflower (*Helianthus annuus) could be considered the most grandiose example. The capitulum consists of:

• ‘ray florets’ which are the petal-like structures which radiate around the centre of the capitulum;  these are a modified flower consisting of an elongated perianth tube which hides sexual structures at the base;
• and ‘disc florets’ – the very small modified flowers in the central disc which have a much reduced perianth and are somewhat tubular with sexual structures.

In some daisies, a range of variations are thrown up such as an absence of ray florets; purely male or female disc florets; and some discs having an involucre of bracts rather than ray florets. A sunflower would have hundreds of disc florets in the centre, surrounded by its larger petal-like yellow ray-florets.

In Ozothamnus spp., the capitula are arranged in tight terminal corymbs or clusters. The capitula (or heads) themselves have an overall globose to oblong or campanulate shape. There are no ray florets. Instead, there are tiny disc florets surrounded by an involucre – a whorled overlapping arrangement of papery bracts. The florets are mainly bisexual with a few female-only.

In this species, the corymbs can be up to 7 to 8 cm across by 5 cm long. Each capitulum is about 3 mm by 3 mm wide. Overall, the papery bracts provide most of the colour and are mostly white but can be pink, appearing in winter and spring. Even though individual capitula are very small, they can be produced profusely in many corymbs, creating a nice display. Each capitula starts off as globose structures in bud, and then open wide and appear as a very small daisy.

The fruit of Ozothamnus (and many daisies) is an achene – a small fruit with one seed surrounded by a very thin outer wall and with a ring (pappus) of bristles attached which aids wind dispersal. Ozothamnus have four-angled achenes, usually only a few millimetres long.