Petrophile sessilis Sieber ex Schult.

Taxon Name and Growth Form

Petrophile sessilis Sieber ex Schult. is an erect shrub that typically reaches a height of 3 meters (9.8 feet).

Young Branchlet and Leaf Indumentum

When young, its branchlets and leaves are covered in silky hairs, becoming hairless (glabrous) as they mature.

Leaf Characteristics

Its leaves range from 30 to 100 millimeters (1.2 to 3.9 inches) long, and are divided into rigid, sharply pointed, needle-shaped pinnae that are usually less than 10 millimeters (0.39 inches) long.

Inflorescence Structure

Flowers are arranged at the ends of branchlets and in leaf axils, forming spike-like oval flower heads 20 to 25 millimeters (0.79 to 0.98 inches) long, with broadly egg-shaped involucral bracts at the base of each head.

Individual Flower Features

The individual flowers are 10 to 14 millimeters (0.39 to 0.55 inches) long, covered in silky hairs, and creamy-yellow in color.

Flowering Period

Flowering occurs mainly from May to February.

Fruit Characteristics

The fruit is a nut, and multiple nuts fuse together into an oval head up to 35 millimeters (1.4 inches) long.

Distinguishing Trait from Related Species

This species can be told apart from the closely related Petrophile pulchella by its finely hairy new growth.

Habitat and Distribution

Petrophile sessilis grows on sandstone soils in heath, woodland, and forest habitats, ranging from the Central Coast to the Central and Southern Tablelands of New South Wales.