none at flowering time --10.

9b. Leaves a single pair, basal, or opposite on the stem; never
alternate on the stem --19.

9c. Leaves several, all basal, prominently net-veined, and frequently
blotched with white (scape 1-4 dm. high; flowers whitish, pubescent,
in summer) (Rattlesnake Plantain) --26.

9d. Leaves 2 or more, on the stem --28.

10a. Foliage leaf absent or undeveloped at flowering time, or
merely persisting through the winter from the previous year
--11.

10b. Foliage leaf present at flowering time --12.

11a. Flower rose-purple, 3-5 cm. long, solitary or two (1-3 dm. high,
early summer) =Arethusa, Arethusa bulbosa.=

11b. Flowers purplish-green, in racemes, with a spur 2 cm. long
=Crane-fly Orchis, Tipularia discolor.=

11c. Flowers yellowish, purple tinged, in racemes; spur none (3-4 dm.
high, early summer). =Putty Root, Aplectrum hyemale.=

12a. Leaf linear or linear-lanceolate --13.

12b. Leaf of a broader shape --14.

13a. Flower solitary or two; leaf just below the flower --11a.

13b. Flowers in a loose raceme, sometimes only 2; leaf basal
=Calopogon, Calopogon pulchellus.=

14a. Flowers greenish, yellowish, or white --15.

14b. Flowers pink to purple, often variegated --17.

15a. Flowers 6-10 mm. wide, with a spur about the same length (1-4 dm.
high, summer) (Rein Orchis) --35.

15b. Flowers 5 mm. wide or less; spur none (1-2 dm. high; summer)
(Adder's Mouth) --16.

16a. Pedicels less than 5 mm. long; lip broadest below the middle
=Adder's Mouth, Microstylis monophyllos.=

16b. Pedicels more than 5 mm. long; lip broadest near the apex
=Adder's Mouth, Microstylis unifolia.=

17a. Flowers spicate; lip distinctly 3-lobed (1-2 dm. high; early
summer) --24.

17b. Flowers solitary or two --18.

18a. Leaf on the stem, lanceolate to ovate --34a.

18b. Leaf basal, round-ovate (2 dm. high or less; early summer)
=Calypso, Calypso bulbosa.=

19a. Leaves opposite and sessile near the middle of the stem (1-3 dm.
high; flowers in summer) (Tway-blade) --20.

19b. Leaves basal --21.

20a. Lip deeply 2-cleft (flowers purplish)