Flora of North America species comparison

Oxalis debilis appears to be spreading rapidly in the United States. The species produces numerous bulblets in a basal cluster and apparently also can spread laterally by production of bulblets at the tips of filiform roots or rhizomes; it can form large, dense colonies. A. Lourteig (1980) noted that plants of this species occasionally fruit but consistently reproduce through abundant bulblets. They apparently are seed-sterile in North America.

Oxalis corymbosa and O. debilis were differentiated by A. Lourteig (2000) primarily by the distribution of oxalate deposits in the leaf lamina. In O. debilis, the dotlike deposits are crowded along the margins and absent to distinctly less abundant elsewhere. In O. corymbosa, the deposits are evenly distributed over the whole lamina. In their native range in South America, the two expressions are broadly sympatric and intermediates are common, as they are in the flora area. Intermediates have the oxalate dots along the margins as well as over the whole surface or sometimes mostly on the outer third of the blades, near the margins. There is no justification for formal recognition of two entities.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Decumbent stems of Oxalis dillenii often appear stolonlike, producing erect branches and leaves at the nodes, rarely producing a few adventitious roots. Such plants sometimes are misidentified as O. corniculata, but they differ in their overall habit, stems and rhizomes that become woody, reduced stipules, strigillose cauline vestiture, denser fruit vestiture, and seed color. Plants of O. dillenii in Canada and the western United States appear to be adventive.

Plants of Oxalis dillenii flowering into November and December in Texas and North Carolina, and probably elsewhere, characteristically are depressed in habit, with creeping stems and forming matlike colonies. The corollas are small, with petals 2.5–3 mm. Although similar in habit to typical O. corniculata, these plants do not have stems that root at nodes, and the strigillose vestiture, though reduced in density, and the stipule morphology are like O. dillenii. Whether these are the same genotype as spring-flowering plants or a different entity remains to be investigated. At least some of the variability in O. dillenii, particularly in habit, may be genetically partitioned, as dysploid chromosome races apparently exist.

(Discussion copyrighted by Flora of North America; reprinted with permission.)