Parkinsonia microphylla

Parkinsonia microphylla
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fabales
Family:	Fabaceae
Subfamily:	Caesalpinioideae
Tribe:	Caesalpinieae
Genus:	Parkinsonia
Species:	P. microphylla
Binomial name
Parkinsonia microphylla (Torr.)

Parkinsonia microphylla (Yellow Palo Verde or Foothill Palo Verde; syn. Cercidium microphyllum) is a species of palo verde native to the southwestern United States (southeastern California, southern Arizona) and northwestern Mexico (Sinaloa, Sonora, Baja California).

Overview

Foothill Palo Verde pictured near the Superstition Mountains (Arizona)

It is a bristling, upright-branching tree, mostly found on slopes, and is one of the most common trees of the Sonoran Desert. The species is slow-growing, sometimes living for several hundred years. It typically grows to heights of around 5 m, although rarely it can reach 6–7 m tall. The leaves are yellowish green, and during extensively dry and hot periods the tree will shed them.

Flowers

The flowers of the palo verde, found on the end of a branch, are small, pale yellow and flower in late spring. The tree may not flower every year, depending on the amount rainfall. If there is enough rainfall, seeds will also appear in 4–8 cm long, soft pods which dip in between each seed. They ripen in July, and stick to the branches. Rodents will often carry and store the seeds underground, where some of them will germinate after a rainy season. The seedlings are very sensitive to drought for the first two to three months of their lives, and only about 1.6% will survive after germinating.

Lost Dutchman State Park (Arizona)

The Palo Verde has the characteristic of performing photosynthesis in its bark (hence the green color), and this is what allows it to survive after it has shed its leaves in hotter periods.

Uses

The Seri people, a Native American group of northwestern Mexico, call this tree ziipxöl [ ʃiːpχʷɬ ]. They used to grind up the seeds for flour, boil the green pods with meat, and eat the sweet green seeds as well as the flowers. They also strung the seeds for necklaces.

Threats

Buffelgrass, an exotic species of grass native to Africa and first introduced into the Sonoran desert for livestock grazing, spreads very quickly and will often kill palo verdes by taking away nearby water, which could pose a serious threat to the tree in the future.

References

• Germplasm Resources Information Network: Parkinsonia microphylla

• Felger, Richard; Mary B. Moser. (1985). People of the desert and sea: ethnobotany of the Seri Indians. Tucson: University of Arizona Press. 

External links

• FEIS entry