Caesalpinia gilliesii (yellow bird-of-paradise)

Caesalpinia gilliesii (Wall. ex Hook.) Wall. ex D. Dietr.

Poinciana gilliesii Wall. ex Hook.

Yellow bird-of-paradise, desert bird-of-paradise, bird-of-paradise shrub

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	Caesalpinia	Named after Andrea Cesalpino (1519-1603) of Italy
Species	gilliesii	Several sources say it was named for John Gillies, an early 19th century botanist in Argentina; but the Darwin Correspondence Online Database has a reference to a John Gillies (1792-1834) who was a naval surgeon who went to Buenos Aires in 1820 and collected plants in Chile and Argentina, returning to Scotland in 1829

About plant names...

The yellow bird-of-paradise is a small tree or shrub, originally from Argentina. The plant has become naturalized through much of the American southwest. It is popular as an ornamental plant. See also the red bird-of-paradise.

Identification: Plants are as high as 10' (3 m), spreading 4-6' (1.2-1.8 m). Leaves are “bipinnate”—in opposing groups of opposing groups. Enlarge the photo below to see the leaves. The fruits are curled fuzzy tan pods. The bright yellow flowers have long thin red stamens.