Platanthera orbiculata (Pursh) Lindley. Subgenus: Platanthera. Section: Lysias. Large Round-leaved Orchid, Dessert-plate Orchid. Phen: Jun-Sep. Hab: Moist hardwood forests and seeps, especially over mafic, calcareous, or other more nutrient-rich substrates. Dist: NL (Newfoundland) and NL (Labrador) west to AK, south to PA (and in the mountains to NC and TN), OH, IN, MN, SD, and OR.

Origin/Endemic status: Native

Taxonomy Comments: Reddoch & Reddoch (1993) showed that P. orbiculata differs from P. macrophylla at species rank.

Other Comments: Pollination is by night-flying moths, likely noctuids.

Synonymy: = FNA26, Il, K3, K4, Mi, NE, NY, Pa, Tn, Va; = Habenaria orbiculata (Pursh) Hook. var. orbiculata – C, F; = Lysias orbiculata (Pursh) Rydb. – S, S13; = Platanthera orbiculata (Pursh) Lindl. var. orbiculata – K1, Luer (1975); < Habenaria orbiculata (Pursh) Hook. – G, RAB, W, WV, Correll (1950); > Habenaria orbiculata (Pursh) Hook. var. lehorsii Fernald – F

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Wetland Indicator Status:

• Eastern Mountains and Piedmont: FAC
• Great Plains: FAC
• Midwest: FAC
• Northcentral & Northeast: FAC

Heliophily ?: 3