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Spiranthes
See list of 8 species in this genusReferences: Sheviak (1982), Sheviak and Brown (2002).
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1a. Labellum with a deep, subapical constriction at ca. ⅔ distance from the base, prominently veined, the branches of the veins wide-spreading toward the margins
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1b. Labellum at most slightly constricted near the apex, if at all, with obscure to prominent veins that have parallel to somewhat diverging branches ( S. lucida with short, widely diverging vein branches)
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2a. Viscidium oval, 2–2.5 times as long as wide; perianth consisting of white sepals and lateral petals, the labellum with a large, bright yellow or orange-yellow area with green veins near the center; plants flowering in June through July, the lustrous basal leaves persisting long after anthesis
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2b. Viscidium lanceolate to linear, 3–12 times as long as wide; perianth not combining the above characteristics; plants flowering July through early October, the basal leaves senescing prior to or soon after anthesis
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3a. Rachis of inflorescence glabrous
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4a. Labellum white; root solitary (rarely divided at the tip), 4–12 mm wide; flowers flaring open from near the middle, the basal tubular portion shorter than 3 mm
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4b. Labellum white with a central green or yellow-green spot; roots few to several, up to 7.5 mm wide; flowers flaring open at ca. ⅔ their length, the basal tubular portion longer than 3 mm (in part)
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3b. Rachis of inflorescence pubescent
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5a. Rachis of inflorescence mostly or entirely pubescent with non-glandular hairs [Fig. 178]; glands of rachis, if present, narrower or equal to width of stipe, therefore, the hairs pointed or cylindrical
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5b. Rachis of inflorescence pubescent, in part, with glandular hairs [Fig. 176]; glands of rachis wider than stipe, therefore, the hairs capitate at their apex
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6a. Inflorescence with 5 or more flowers per cycle of spiral, therefore, the spiral of flowers open and easily discernible; labellum 3.5–8 mm long
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7a. Leaves narrow-ovate to obovate, 1–3.5 times as long as wide, strictly basal (sometimes withering prior to anthesis); labellum with a central green or yellow-green spot (in part)
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7b. Leaves narrow-lanceolate to oblanceolate, mostly 5–10 times as long as wide, basal and also on lower stem; labellum cream-white to green-white, sometimes yellow near center
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6b. Inflorescence with 3 or 4 flowers per cycle of spiral, therefore, the spiral obscure and the inflorescence dense, with flowers appearing arranged in vertical ranks; labellum (6–) 7.5–12 mm long
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8a. Blade of labellum strongly curving downward from claw, the interior angle (i.e., measured on the abaxial face) 120–155 degrees [Fig. 177]; claw of labellum 0.8–1.5 mm long; maximum separation of lateral sepals from dorsal sepal mostly 0.5–1.1 mm [Fig. 177]; basal calli of labellum (0.8–) 1–1.6 (–2) mm long
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Each photo represents one species in this genus.