The Blue Jacaranda, Jacaranda mimosifolia more often known simply as the "Jacaranda", is a sub-tropical tree native to South America that has been widely planted elsewhere because of its beautiful and long-lasting blue flowers. Older sources give it the systematic name Jacaranda acutifolia, but it is nowadays more usually classified as Jacaranda mimosifolia. It is also known as the Black Poui, or as the fern tree. In scientific usage, the name "Jacaranda" refers to the genus Jacaranda, which has many other members, but in horticultural and everyday usage, it nearly always means the Blue Jacaranda.

　 The tree grows to a height of 5 to 15 metres. Its bark is thin and grey-brown in colour, smooth when the tree is young though it eventually becomes finely scaly. The twigs are slender and slightly zigzag; they are a light reddish-brown in colour. The flowers are up to 5 cm long, and are grouped in 30 cm panicles. They appear in spring and early summer, and last for up to two months. They are followed by woody seed pods, about 5 cm in diameter, which contain numerous winged seeds. The Blue Jacaranda is cultivated even in areas where it rarely blooms, for the sake of its large compound leaves. These are up to 45 cm long and bi-pinnately compound, with leaflets little more than 1 cm long.