Eucalyptus gomphocephala, known as tuart, is a species of tree, one of the six forest giants of Southwest Australia. Tuart forest was common on the Swan coastal plain, until the valuable trees were felled for export and displaced by the urban development around Perth, Western Australia. The wood is dense, hard, water resistant and resists splintering, and found many uses when it was available. Remnants of tuart forest occur in state reserves and parks, the tree has occasionally been introduced to other regions of Australia and overseas. Remaining trees are vulnerable to phytophthora dieback, an often fatal disorder, including a previously unknown species discovered during analysis of dead specimens.
Description
The tree is native to the southwest of Western Australia and typically grows to a height of . The tallest known living tuart is 47m tall and located in the Tuart Forest National Park near Ludlow. The largest tuart tree has a wood volume of . Taller trees are often found at the southern end of the trees range while smaller trees are found at the northern end. The crown of the tree can spread up to a width of . The habit of tuart is a tall single stemmed tree, but may form a low and multi-stemmed tree at the edge of stands in response to salinity and winds. The trees have no lignotuber but will form epicormic buds up along the stem.
Tuart has box-like rough bark over the length of the trunk and the main branches. The bark is rough and finely fibrous and grey in colour and breaks into smaller flaky pieces. On large and older stems the bark tends to become tessellated. The branchlets have a circular cross-section often have oil glands situated in the pith but sometimes there are not many and can be tough to find.
Juvenile leaves are attached to the stem via a stalk always have an opposite arrangement for the first four to eight nodes along the stem then have an alternate arrangement. The green and discolorous juvenile leaves have an egg-shaped (ovate) to cordate shape with a length of and a width of . Adult leaves are stalked, alternate, with an oval to lanceolate or falcate shape. The leaves are slightly discolorous to concolorous, glossy, light green and thin. The leaf blade is in length and wide and often curved. that branch off at an angle of apex of the leave is pointed and the base tapers to the petiole, the leaves have few oil glands, are densely reticulated where the veins are packed in tightly forming a dense network in the leaf and have side veins that branch off at an angle of over 45° to compared to the midrib.
The tree flowers between January and April and tends to have a mass flowering event every five to eight years with smaller intermittent flowering for the years in between. White to cream flowers appear in mid-summer to mid-autumn between January and April. The inflorescences form in the leaf axils and are not branched. The peduncle has a length of with seven buds in each umbel that are attached by long pedicels. The buds have swollen caps, said to resemble a small ice cream cone, the caps are long. The buds are in length and have a width of with a hemispherical shaped operculum that are wider than the obconically shaped hypanthium located below. When the outer opercula is shed a scar is left. The stamen are flexed irregularly and contain an oblong anther that is attached at the rear to the filament. The anther can burst open via longitudinal slits. The style is straight and long with a blunt stigma at the tip. the style has a small cavity at the base (or locule) holds the ovary with four vertical rows of ovules. The flowers are formed in tight clusters made up of around seven flowers. These later form into fruits with a mushroom shape containing small seeds.
The fruits are narrow and in length with a broad rim and wide. The fruits are attached to the stem via long pedicels. The fruits have an obconic to upside-down bell shape and sometimes have two longitudinal ridges that extend from the pedicel partly along the length. The fruits has a level disc that can be slightly raised or descending and has three to five valves that are partly protruding or exserted.