Dillwynia retorta

A usually upright shrub to 3 metres high (prostrate in some habitats), spreading to over 1 metre wide, with stems covered in short hairs.

It is a recognised species-complex with a range of forms. It is accepted as growing naturally in NSW and Queensland only, north from about the ACT and further east, with high concentrations of records from Jervis Bay and further north along the coast, through Sydney and the Blue Mountains, to as far west as around Orange, then in scattered patches along the western slopes, tablelands and coast, to Fraser Island and Hervey Bay, and inland in Carnarvon National Park, in Queensland.

It grows in heath, shrubland, dry sclerophyll woodland and forest, usually on sandstone or sandy soils.

Dillwynia is a member of the “pea” family. This generally means that leaves are alternate with stipules at the base of the petioles. Dillwynia have simple and alternate leaves, with stipules present and minute, or absent.

Leaves can be flat, terete or triangular in cross-section and often twisted.

In this species, leaves are crowded along the stems; linear, spirally twisted and smooth with the upper surface grooved, 15 mm long and only 1 mm wide. The foliage is smooth and soft to touch.

Flowers are, of course, pea-shaped (a term sometimes used is papilionate), with 5 petals in a fixed arrangement; the main back petal is called the “standard”, two lateral petals called “wings” and two fused petals at the bottom called the “keel” (in which the anthers and one carpel tend to be hidden).

In Dillwynia, flowers are yellow, or red and yellow (or orange/yellow) and are usually arranged singly or in small groups in leaf axils or on the ends of branchlets. The upper two of five sepal lobes are joined in a single “lip”. The standard petal is typically wider than high (a useful identification feature), and the keel is the same length as the wings. There are very small leafy bracts present on the common peduncle (which can fall early or be persistent) and bracteoles on flower pedicels (below the calyx).

In this species, flowers can be produced singularly, or are in umbel- or raceme-like clusters, at the terminals and upper leaf axils, with up to 9 flowers per cluster; yellow in colour, with the standard to 12 mm long and bearing red markings, occurring from June to November.

The fruit of all peas is a pod. In this species, they are approximately 7 mm long, with seeds smooth.