Jacaranda

Scientific Name : Jacaranda mimosifolia D. Don
Common Name : Jacaranda
Chinese Name : 藍花楹
Family : BIGNONIACEAE
Local distribution status : Exotic species

Anecdotes on plants

Origins Brazil, Bolivia and Argentina.
Applications The Jacaranda has lush branches and leaves, and its canopy has clear visible layers. Entering the flowering period, the tree is dyed purplish-blue by its flowers, whose endless blooms mimic brocade and lend to its popularity in being planted as street trees and gardening plants in the tropical and subtropical regions. Furthermore, the wood of the Jacaranda is light and soft, easy to be processed, and has a straight grain, which can be used as the raw material for furniture.
Similar species Jacaranda has the name “Blue-flower Pillar (藍花楹)” in Chinese, can be compared with the Flame Tree, which is also known as “Red-flower Pillar (紅花楹)” in Chinese. Their appearances are similar, and if neither flowers nor fruit are present, it is easy to confuse them without careful observation. The compound leaves of the Jacaranda are shorter, about 15 to 30 cm, while the compound leaves of the Flame Tree are longer, around 20 to 60 cm. The leaflets on each pinna of the Jacaranda are odd numbers, with the leaflets narrowly elliptic, with “pointed tips”, and the margin slightly curled; the leaflets on each pinna of the Flame Tree are even numbers, with the leaflets oblong, with obtuse apex, and uncurled margin.
As the Chinese names imply, the flowers of the Jacaranda are purplish blue, while the flowers of the Flame Tree are bright red. While the petals of the Jacaranda are fused into a funnel shape, the petals of the Flame Tree are separated and clawed (narrowed base of petal). The fruit of the Jacaranda is relatively small, as a flat round capsule, akin to a bell; the fruit of the Flame Tree is huge comparatively, which the pod is in length similar to an arm of human. Although these two species share similar appearance, they are different plants indeed. The Jacaranda belongs to Bignoniaceae, while the Flame Tree belongs to Caesalpiniaceae, thus the phylogenetic relationship between the two are rather separated.

Traits for identification

Growing habit Deciduous tree.
Height To 15 m.
Stems Bark of trunk greyish brown, with longitudinal cracks. Diameter at Breast Height (DBH) of main trunk to 45 cm.
Leaves Bipinnately compound, opposite. More than 10 pairs of pinnae on each compound leaf, 35 to 51 leaflets on each pinna, rachis of pinnae with narrow wings. Lateral leaflets narrowly elliptic, apex abruptly acuminate, margin slightly revolute, papery, subsessile. Terminal leaflets larger, ovate-lanceolate, apex long-acuminate.
Flowers Purplish blue. Inflorescences terminal, many-flowered. Corolla funnelform, somewhat bilabiate. Corolla tube slender, long and slightly curved at the lower part, swollen at the upper part, apex 5-lobed, lobes suborbicular. The middle lobe on the lower lip longer, the other 4 lobes subequal in length.
Fruits Capsules oblate, woody, thicker at middle part, thinning outwards, uneven, dark brown when mature. Shaped like a bell.
Seeds Flattened, suborbicular, with transparent membranous wings.
Flowering period April to June in Hong Kong.
Fruiting period May to October in Hong Kong.
Remarks

Scientific name above is based on Hong Kong Herbarium website : https://www.herbarium.gov.hk/en/hk-plant-database/plant-detail/index.html?pType=species&oID=9676

Scientific names from other databases
Plants of the World Online : Jacaranda mimosifolia D.Don

Reference