Oxalis caerulea (Blue Woodsorrel)

Oxalis caerulea (Blue Woodsorrel)

Family
OXALIDACEAE
Synonyms
IONOXALIS CAERULEA
Common Name
Blue Woodsorrel

Description
This species is (supposedly) distinguished from the more common Oxalis alpina and O. drummondii by having extended flanges at the petiole bases and two or more oxalate deposits at the distal end of each leaflet lobe.
Distribution
Denton (1973) gives a range of southern Rockies of NM south to southern Durango, Mexico.
Remarks
The above are all very old (pre-1925) collections. The Fendler collection was made during his first year in Santa Fe, so I assume it is from that vicinity. There are no sheets of this plant at UNM and I am surprised it has not been recently collected. Two of the Oxalis alpina collections (UNM) from the Black Range have slightly expanded petiole bases, but I would not call them flanges. Also, the location of oxalate deposits is variable for sheets labeled O. alpina so I wonder about the significance of this characteristic. Denton lumped a lot of names into O. alpina and O. decaphylla, yet she kept O. caerulea as a distinct species and places its affinity with the Mexican and Central American O. lunulata.
Conservation Considerations
This species is widespread from northern NM to the southern Sierra Madre. It is either rare in NM or very difficult to accurately identify. I don't know its status in Mexico.
Important Literature

Denton, M.E. 1973. A monograph of Oxalis, Section Ionoxalis. Biological Series, Vol. 4, No. 10. Publications of the Museum, Mich. State Univ., East Lansing.

Shreve & Wiggins 1964. Flora of the Sonoran Desert. Stanford Univ. Press.

Turner, B.L. 1994. Regional variation in the North American elements of Oxalis corniculata Phytologia 77:1-7.

Information Compiled By
Robert Sivinski

For distribution maps and more information, visit Natural Heritage New Mexico