Corallorhiza odontorhiza (Willdenow) Poiret. Phen: Aug-Sep; Oct. Hab: Mesic to dry forests, especially under oaks. Dist: The cleistogamous form (or recognized as var. odontorhiza) is the more common, and is widespread in e. North America, from ME, NY, s. ON, MI, and MN south to SC, c. GA, ne. FL, c. AL, n. MS, c. AR, and e. OK.
Origin/Endemic status: Native
Taxonomy Comments: Freudenstein (1997) stated that Corallorhiza odontorhiza var. pringlei can be distinguished from var. odontorhiza by the presence of a closed perianth, a narrowly obovate-spatulate lip, and a column with two prominent auricles on the ventral surface (vs. perianth open, lip similar to perianth, and a column poorly developed or lacking). The cleistogamy seems to be a popular proxy for varietal designation; however, both flower types apparently exist within the same populations with seemingly no ecological or phenological separation. Adding to the complications is the confusing gap in lip width between C. odontorhiza var. pringlei f. pringlei (2.1-3.7 mm) and C. odontorhiza var. pringlei f. radia (1.2-1.7 mm) conveniently coinciding with the lip width in C. odontorhiza var. odontorhiza (1.7-2.2 mm). Lastly, it seems unlikely that co-occurring plants in n. North America are less related than to the plants of sc. Mexico. Freudenstein (1997) stated that it is desirable to recognize different morphologies, but also states that it is not clear how each variety was related, an issue still not resolved as major gaps remain regarding the geography, ecology, and phenology of Corallorhiza odontorhiza across its far-reaching and disjunct range. The chasmogamous form is less common, and is scattered in ne. United States and adjacent Canada, in ON, CT, PA, MI, IA, IN, DC, NC, and TN, and in Mexico (Chiapas, Distrito Federal, Guerrero, Hidalgo, Jalisco, México, Michoacán, Morelos, Oaxaca, Puebla, Sonora), Guatemala, and Nicaragua. It is sometimes recognized as var. pringlei (see synonymy), but does not seem to breed true and so seems better regarded as a form. The rarer chasmogamous form "var. pringlei" has the perianth open (chasmogamous); lip 2.1-3.7 mm wide, bent downward at a nearly right angle; column with 2 prominent auricles at the base on the ventral surface; stigma 0.7-1.0 mm wide. The more common cleistogamous form ("var. odontorhiza") has the perianth closed or nearly so (cleistogamous); lip 1.7-2.2 mm wide, straight; column lacking or with only poorly developed basal ventral auricles; stigma 0.2-0.5 mm wide.
Synonymy: = C, ETx1, F, G, Il, K3, K4, Mo1, Pa, RAB, Va, W, WH3, WV, Correll (1950), Luer (1975); > Corallorhiza odontorhiza (Willd.) Poir. var. odontorhiza – Ar, FNA26, K1, Mi, NE, NY, Tn, Freudenstein (1997); > Corallorhiza odontorhiza (Willd.) Poir. var. pringlei (Greenm.) Freudenst. – FNA26, K1, Mi, NE, NY, Tn, Freudenstein (1997); > Corallorrhiza micrantha Chapm. – S; > Corallorrhiza odontorhiza – S, orthographic variant; > Corallorrhiza pringlei Greenm.