Dillwynia tenuifolia

An erect shrub to a height of about 1 metre, spreading to over 0.5 metres wide, with stems covered with shortly-curved hairs.

It mainly occurs in the Sydney area, on the Cumberland Plain but also further afield. Occurrences include as far north-west as Kurrajong Heights, as well as Falconbridge-Hazelbrook in the Blue Mountains. It has large populations in western Sydney, especially in the nature reserves on the Cumberland Plain. It extends up from Windsor, towards Wisemans Ferry, and as far south as Liverpool. Disjunct occurrences are also known from near Morisset, as well as the Bulga Mountains near Broke.

It is typically found in dry sclerophyll woodland and forest, on clay to alluvial soils, especially the Cooks River Castlereagh Ironbark Forests and Shale-Gravel Transition Forests.

It is a listed threatened species.

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 linear, glabrous or sometimes hairy near the tip, to 12 mm long and less than 1 mm wide, often soft and weeping; mid to dark green in colour. The foliage has an overall soft feel.

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, orange-yellow flowers are usually arranged singly or in pairs, in leaf axils or on the ends of branchlets, with the standard to 10 mm long, bearing striking red markings, occurring from February to March but also at other times.

The fruit of all peas is a pod. In this species, they are approximately 5 mm long with a reticulate pattern on the seeds.