About Corymbia ptychocarpa (F.Muell.) K.D.Hill & L.A.S.Johnson
Corymbia ptychocarpa (F.Muell.) K.D.Hill & L.A.S.Johnson is a tree that typically grows to a height of 4.5 to 20 metres (15 to 66 ft). It has thick, rough, tessellated, brownish bark covering its trunk and branches, and typically grows as a crooked tree that tends to lean or bend when young, often developing drooping branches. Young plants and coppice regrowth have petiolate leaves that range from oblong to round or elliptical in shape, and become egg-shaped as they mature; these leaves measure 60–300 mm (2.4–11.8 in) long and 70–130 mm (2.8–5.1 in) wide. Adult leaves are leathery, paler on their lower surface, broadly lance-shaped, and measure 110–460 mm (4.3–18.1 in) long and 27–130 mm (1.1–5.1 in) wide, tapering to a 15–40 mm (0.6–1.6 in) long petiole. The midrib of adult leaves is pale yellow, which contrasts with the green leaf blade, and the lateral veins are arranged parallel to one another. Flowers are borne at the ends of branchlets, on a branched peduncle 10–60 mm (0.4–2.4 in) long. Each branch of the peduncle holds seven flower buds, each on a 10–34 mm (0.4–1.3 in) long pedicel. Mature buds are oval to pear-shaped, 13–24 mm (0.51–0.94 in) long and 11–18 mm (0.43–0.71 in) wide, with a rounded to blunt-conical operculum. Flowering occurs from February to May, and produces flowers that are creamy yellow, pink, or red. The fruit is a woody, barrel-shaped capsule 32–55 mm (1.3–2.2 in) long and 26–45 mm (1.0–1.8 in) wide, with around eight sharp ribs along its sides, and valves enclosed inside the fruit. This species is distributed from the Kimberley region of Western Australia, through the Top End of the Northern Territory, to near Doomadgee in far north-western Queensland. It grows in sandy soils and alluvium along watercourses and near springs. In the Northern Territory, it occurs in the Arnhem Plateau, Daly Basin, Ord Victoria Plain, Pine Creek, and Victoria Bonaparte biogeographic regions. Subspecies aptycha is restricted to the Top End between the Cobourg Peninsula, Yirrkala, and El Sharana in Arnhem Land. Corymbia ptychocarpa is also grown as a street tree in parts of Queensland, including Cairns and Townsville.
