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See list of 21 genera in this family
  • 1a. Labellum deeply concave to saccate (at least in the basal portion), forming a small to 
very evident pouch [Fig. 164]
    • 2a. Labellum saccate in only the basal portion, 1.8–12 mm long; inflorescence a spike or raceme, with 5–72 flowers [Fig. 166]
      • 3a. Principal leaves all basal, usually white-striped or white-reticulated [Fig. 165]; labellum white to white-green
      • 3b. Principal leaves borne on the stem, alternate, without white markings; labellum purple to purple-brown with pink near the apex or dark red
    • 2b. Labellum saccate ± throughout, 10–67 mm long; inflorescence a solitary flower or a spike-like raceme with 2 or 3 (–4) flowers
      • 4a. Labellum with 2 apical horns and a prominent fringe of yellow bristles; plants with 
1 leaf; flowers with 1 fertile anther; stem arising from a corm
      • 4b. Labellum without a pair of apical horns, lacking evident yellow bristles [Figs. 163,164]; plants with 2 or more leaves; flowers with 2 fertile anthers; stem arising from a short to elongate rhizome
  • 1b. Labellum neither inflated nor saccate, not forming a pouch [Figs. 167,171,174]
    • 5a. Labellum basally prolonged into a hollow spur (the spur short and saccate in Coeloglossum) [Figs. 173,175]
      • 6a. Flowers bilaterally asymmetrical (i.e., appearing lopsided); leaf single, abaxially purple, produced in autumn, withering by early spring, therefore, the flowering 
plants without well-formed leaves
      • 6b. Flowers bilaterally symmetrical; leaves 2 or more, less commonly single, abaxially green, produced in spring and present during flowering
        • 7a. Labellum white with magenta spots, 3-lobed, the middle lobe notched at the apex; leaf single, basal
        • 7b. Labellum not spotted, variously shaped but never 3-lobed with a notched middle lobe; leaves 1–several, basal or arranged on a stem
          • 8a. Stems conspicuously angled; labellum unlobed, typically white and strongly contrasting in color from the pink-magenta sepals and lateral petals (rarely 
all the perianth of similar color); viscidia enclosed in a single, 2-lobed bursicle
          • 8b. Stems terete; labellum unlobed, lobed, or fringed, ± similar in color to the remainder of the perianth (those Platanthera with 2 basal leaves usually have the sepals more strongly tinged with green than the petals); viscidia free, not enclosed in a bursicle
    • 5b. Labellum lacking a spur (flowers with a small, inconspicuous, adnate spur in Corallorhiza formed by the 2 lateral sepals) [Figs. 167,170,177]
      • 12a. Flowers not resupinate, the labellum the uppermost petal; labellum with a conspicuous brush of yellow-tipped hairs; leaves articulated, this appearing as a 
thin, transverse line near the base of the leaf
      • 12b. Flowers resupinate, the labellum the lowest petal; labellum with or without hairs 
or ornamentation of some type; leaves not articulated
        • 13a. Leaves whorled at the summit of the stem
        • 13b. Leaves or scales alternate or opposite, borne at base of plant and/or distributed along the stem
          • 14a. Flowers subtended by foliaceous, ovate bracts [Fig. 179]; labellum ornamented with 3 parallel, green, papillose ridges [Fig. 179]
          • 14b. Flowers subtended by rather inconspicuous, usually scale-like bracts; labellum ornamented or not, never with 3 parallel, green ridges
            • 15a. Flowers large, the labellum (12–) 17–35 mm long; flowers usually solitary
              • 16a. Leaves flat, numbering 1–3 on the stem, present at anthesis, the largest 7–25 (–32) mm wide; sepals and lateral petals distinct, the outer spreading
              • 16b. Leaves obscurely plicate, solitary on the stem, not fully formed at anthesis, 2–4 (–12) mm wide; sepals and lateral petals connate at the base, the outer erect
            • 15b. Flowers smaller, the labellum 1.3–12 mm long; flowers 3–180 per inflorescence
              • 17a. Principal leaves arranged in a single, opposite pair on the stem; labellum 2-lobed due to a conspicuous apical notch [Figs. 170,171]
              • 17b. Principal leaves 1–several, borne at base of plant and/or distributed along the stem; labellum entire or 3-lobed, without a single apical notch (with a prominent notch in Malaxis, but then with a small lobe at the base 
of the central notch) [Figs. 169,176]
                • 18a. Flowers predominantly white or cream (except for a yellow or green central area on the labellum in some species), sometimes tinged with yellow or green; leaves and stem bracts above them numbering 5 or more; labellum with a pair of basal callosities
                • 18b. Flowers not predominantly white or cream, variously colored and/or spotted; leaves and stem bracts (when present), numbering 4 or fewer; labellum without a pair of basal callosities
                  • 19a. Plants leafless at flowering time, with sheathing bracts only, arising from coral-like rhizomes; plants without chlorophyll, the stems brown to purple, or yellow-green in one species
                  • 19b. Plants with leaves at flowering time ( Aplectrum sometimes leafless at flowering, but the withered remnant usually present at stem base), arising from corms; plants chlorophyllous, the leaves and stems ± green at anthesis
                    • 20a. Leaf solitary, evidently plicate, produced at distal end of corm in late season and persistent through the winter, usually withering by flowering; labellum white with magenta spots (rarely all white-yellow); capsules pendent
                    • 20b. Leaf solitary or paired, not or only obscurely plicate, produced in spring, present during flowering, withering before winter; labellum green to yellow-green or brown-purple to pale purple, without spots; capsules spreading to erect
                      • 21a. Plants with 2 leaves, in a pair near the base of the stem; labellum 4–12 mm long; capsules 9–13 mm long
                      • 21b. Plants with a single leaf (rarely 2 and then not paired), 
borne on the stem; labellum 1.3–2.3 mm long; capsules mostly 5–8 mm long

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 Show photos of:   Each photo represents one genus in this family.