Vachellia farnesiana (mimosa)

Vachellia farnesiana (L.) Wight & Arn.

Acacia farnesiana (L.) Willd.

Acacia farnesiana (L.) Willd. var. farnesiana

Acacia minuta (M.E. Jones) R.M. Beauch.

Acacia minuta (M.E. Jones) R.M. Beauch. ssp. densiflora (Alexander ex Small) R.M. Beauch.

Acacia smallii Isely

Mimosa farnesiana L.

Pithecellobium minutum M.E. Jones

Vachellia densiflora Alexander ex Small

Mimosa, prickly acacia, sweet acacia, needle bush, huisache

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Rosidae	Roses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more
Order	Fabales	Legumes (pea and bean families)
Family	Fabaceae	Legume family (peas and beans)
Genus	Vachellia	Named after the Rev. George Harvey Vachell (1798-1839), chaplain to the British East India Company in Macao from 1825-1836 and a plant collector in China
Species	farnesiana	From plants grown in Rome in the Farnese Gardens from seed collected in Santo Domingo, in the Dominican Republic

About plant names...

Mimosa is pantropical, found in the Caribbean, the Guianas, from the southern USA to Chile, most of Australia, much of Africa, southern Europe, and southern Asia. It is evergeen over most of its range, but in some habitats it is deciduous. In some areas mimosa is considered an invasive species.

Plants: A small tree or shrub, with multiple trunks. Reaches a height of 6½-23' (2-7 m). Stems are deep brown or gray, covered with long, sharp paired thorns up to 2" (5 cm) in length.

Leaves: Feathery, finely divided, bipinnate, with 2-8 pairs of pinnae and 10-12 pairs of leaflets in each pinna. Leaflets are ¹/₁₆-¼" (2-7 mm) long and ¹/₃₂-¹/₁₆" (0.8-1.8 mm) wide.

Flowers: “Puffballs” are yellow, very fragrant, and ⅜-½" (1-1.5 cm) in diameter. They appear nearly all year. An essential oil called Cassie, which smells like violets, is distilled from the flowers.

Fruits: Pods are glossy, 1½-3" (4-7.5 cm) × ½" (1.5 cm), straight or curved, and pointed on both ends. They are dark brown to blackish, and contain chestnut-brown seeds ¼-⁵/₁₆" (7-8 mm) × ⅛" (4 mm).

Online References:

Vachellia farnesiana at the University of Florida Environmental Horticulture site (PDF)

Vachellia farnesiana at Chris A. Martin's site at Arizona State University

Vachellia farnesiana on Wikipedia

Vachellia farnesiana on Plants for a Future

Vachellia farnesiana on eFloras

Vachellia farnesiana at cabi.org’s Invasive Species Compendium

Vachellia farnesiana at the University of Florida Institute of Food and Agricultural Sciences