Olearia tenuifolia

Olearia tenuifolia is a small shrub reaching a height of about 2 metres with a spread to about 1 metre.

It has somewhat of a sporadic spread in NSW, found from west of Gosford to Dubbo and Tullamore, with Dunedoo being the northern extent; then concentrated between Cowra and Grenfell. There are patchy records west of Wollongong and Nowra with a lot of records around Canberra. It extends in patchy occurrences down to around Bermagui. It also has a patchy distribution across Victoria, occuring across the state, to a line south of Mildura (NSW).

It grows in rocky dry sclerophyll woodlands and forests as well as mallee shrublands.

Olearia spp. have simple and either alternate or opposite leaves. In this species, they are alternate, to about 35 mm long by 3 mm wide, linear in shape and with margins entire or regularly toothed, and with glands on either surface, sticky and aromatic.

Olearia 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 Olearia spp., the flowers are arranged in typical terminal capitula (or ‘heads’) with ray and disc florets. In this species, the heads are produced solitarily at the stem terminals or in small corymbs. Each head is about 3 cm across, with the ray florets blue to mauve and the disc florets yellow. The flowers are profuse, conspicuous and carried for most of the year.

The fruit of Olearia (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.