Parkinsonia aculeata is a species of perennial flowering tree in the pea family, Fabaceae. Common names include palo verde, Mexican palo verde, Parkinsonia, Jerusalem thorn, jelly bean tree.Parkinsonia aculeata may be a spiny shrub or a small tree.
It grows 2 to 8 m (6.6 to 26 ft) high, with a maximum height of 10 metres (33 ft). Palo verde may have single or multiple stems and many branches with pendulous leaves. The leaves and stems are hairless. The leaves are alternate and pennate (15 to 20 cm long). The flattened petiole is edged by two rows of 2-30 tiny oval leaflets; the leaflets are soon deciduous in dry weather (and during the winter in some areas) leaving the green petioles and branches to photosynthesize.The branches grow double or triple sharp spines 7-12 mm long at the axils of the leaves. The flowers are yellow- orange and fragrant, 20 mm (0.79 in) in diameter, growing from a long slender stalk in groups of eight to ten. They have five sepals and five petals, four of them clearer and rhomboid ovate, the fifth elongated, with a warmer yellow and purple spots at the base. The flowering period is the middle months of spring(March& April or September & October). The flowers are pollinated by bees. The fruit is a seedpod, leathery in appearance, light brown when mature.