Jacarandas
Scientific classification
: Plantae  : Magnoliophyta  : Magnoliopsida  : Scrophulariales  : Bignoniaceae  : Jacaranda
Species
about 50, including: Jacaranda acutifolia Jacaranda arborea Jacaranda caerulea Jacaranda caroba Jacaranda caucana Jacaranda copaia Jacaranda glabra Jacaranda mimosifolia Jacaranda obtusifolia Jacaranda praetermissa Jacaranda sparrei

Jacaranda is a neotropical genus in the family Bignoniaceae. Its members range in size from subshrubs to large trees.

As is often the case with plants, the genus name is also used as the common name for cultivated varieties. The most often seen is the Blue Jacaranda tree, to which older sources give the species name Jacaranda acutifolia, though more modern ones call it Jacaranda mimosifolia. This is widely grown for its ornamental value. Other members of the genus are also commercially important; for example the Copaia Jacaranda copaia is important for its timber because of its exceptionally long bole.

Members of the genus Jacaranda differ from other Bignoninaceae by having a staminode that is longer than the stamens, 3-colpate pollen, and a chromosome number of 18. The flowers of most species are blue or blue-purple to magenta, though a few have white flowers.

The genus is divided into two sections, Monolobos and Dilobos, based on the number of theca on the anthers. Section Monolobos has 18 species and is found primarily in the Caribbean, Central America, and western South America; the Blue Jacarandas are included in this section. Dilobos, which is believed to be the primitive form, has 31 species and is found primarily in sub-Amazonian Brazil and the adjacent Parank Valley. The anatomy of the wood in the two sections also differs. Although usually treated in Monolobos, Jacaranda copaia seems to be different from all other members of the genus, and to be intermediate between the two sections.

Reference

• Dos Santos, G., & Miller, R. B. (1997). Wood anatomy of Jacaranda (Bignoniaceae): Systematic relationships in sections Monolobos and Dilobos as suggested by twig and stem rays. IAWA Journal, 18, 369-383. (public domain document, available online)

Side-note: People in Australia sing a Christmas song about Jacaranda trees, as the purple blooms are only seen in summer time - as the song explains, "When the bloom of the jacaranda tree is here, Christmas time is near."