Oxalis caerulea (Small) R. Knuth

Family: Oxalidaceae

Synonyms: Ionoxalis caerulea Small

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.

Plants Seen or Cited: Denton (1973) cites the following collections for NM:
Catron Co.: near Luna (Eggleston 20254, NY, US);
Colfax Co.: vicinity of Ute Park (Standley 13754, US);
Lincoln Co: near Gray (Skehan 112, G, US);
WITHOUT LOCALITY: 1847 (Fendler 91, G, MO);
MEXICAN BOUNDARY SURVEY: between Rio Seco and Sabinal Creek (Schott s.n., NY).

Denton also cites 8 collections for Mexico and gives the habitat as rocky hillsides at elevations between 2000-2300 m.

COMMENTS: 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.

STATUS: 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: Bob Sivinski