Oxalis caerulea, the blue woodsorrel, is a perennial plant and herb in the wood-sorrel family. It is native to the southwestern United States.
Blue woodsorrel is a perennial that grows from a single bulb and does not have rhizomes or stolons. The bulbs measure 8âÂÂ1.5 millimeters long and only infrequently grow bulblets. The scales on the bulb can have three to seven lines, though usually five or more.
All the leaves are basal, growing directly from the base of the plant on individual leaf stems most often measuring 3âÂÂ10 centimeters long, but on occasion reaching 13 cm. Each leaf is made up of three to five leaflets, though most frequently four.
The inflorescence can have one to seven flowers, though at least two is frequent. The leafless flower stem is hairless and measures 6âÂÂ15 centimeters tall. Each flower has five sepals and five petals, pink-lavender to rose-red in color. The petals measure 8âÂÂ10 mm long. Flowering can occur anytime from June to September.
Oxalis caerulea was scientifically described in 1907 by John Kunkel Small, but named Ionoxalis caerulea. It was moved to the genus Oxalis by Reinhard Gustav Paul Knuth in 1919 giving the species its accepted name. Along with its genus it is classified in the family Oxalidaceae.
The species name Oxalis caerulea means "blue" in Botanical Latin and it is likewise known as blue woodsorrel or blue wood-sorrel.
Blue woodsorrel grows in Colorado, Arizona, and New Mexico in the US and Chihuahua, Durango, and Sonora in Mexico. They are found at elevations of .
The species grows along streams and meadows in pinyonâÂÂjuniper woodlands, pineâÂÂoakâÂÂjuniper forests, and quaking aspens.