Listera smallii |
Listera borealis |
|
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Appalachian twayblade, kidney-leaf twayblade |
northern twayblade |
|
Habit | Plants 5–35 cm. | Plants 4–26 cm. |
Stems | slender, succulent, glabrous. |
green, slender to stout, slightly 4-angled, succulent, glabrous. |
Leaves | blade dark green, ovate-reniform, 2–4 × 1.5–3.5 cm, apex acute, mucronate, or apiculate to short-acuminate. |
blade green to dark bluish green, elliptic, ovate-elliptic, or lanceolate, 1.3–6 × 0.7–3 cm, apex obtuse to rounded. |
Inflorescences | 5–15-flowered, lax, 40–100 mm; floral bracts ovate, 3–4 × 1.5 mm, apex acute; peduncle and rachis glandular-pubescent. |
5–20-flowered, lax, 20–90 mm; floral bracts lanceolate, ovate, or oblong, 1–3 × 0.5–1 mm, apex obtuse; peduncle and rachis glandular-pubescent. |
Flowers | green, purple-brown, to pinkish tan; pedicel slender, 6–7 mm, glabrous; sepals strongly reflexed; dorsal sepal lanceolate to linear-lanceolate, 3–4 × 1 mm, apex acute; lateral sepals lanceolate to linear-lanceolate, 3–4 × 1 mm, apex acute; petals slightly reflexed, linear to linear-lanceolate, margins slightly revolute, apex acute; lip sessile, broadly obovate to cuneate, 6–10 × 5–7 mm, base with rounded lobule on each side, apex dilated and deeply cleft into pair of ± divergent broadly rounded lobes, shallowly toothed in sinus; column slightly arcuate, short, 1.5–3 × 1–2 mm. |
pale green, yellowish green, or bluish green with veins darker green; pedicel filiform, 3.5–7 mm, glandular-pubescent; sepals and petals strongly reflexed away from lip and column; dorsal sepal elliptic-lanceolate to linear-elliptic, 4–6 × 1.5–2.2 mm, apex obtuse to rounded; lateral sepals linear-elliptic to oblong-lanceolate, falcate, 4.5–7 × 1.4–2.3 mm, apex obtuse to rounded; petals linear to linear-oblong, falcate, 4.5–5 × 0.7–1.5 mm, apex obtuse; lip oblong, slightly narrowed in center, base with broadly rounded and bluntly angled divergent auricles, apex slightly dilated, cleft into 2 oblong or semiorbiculate lobes, with apicule in sinus; disc 3-veined, lateral veins branched and purplish, base darker green, with ridge in center, thickened along center, 7–12 × 4.2–6.5 mm, margins ciliate; column arcuate, stout, 3–4 × 1 mm. |
Capsules | semierect, ellipsoid, 5 × 3 mm. |
ellipsoid, 8 × 5 mm. |
2n | = 38. |
= 56. |
Listera smallii |
Listera borealis |
|
Phenology | Flowering Jun–Jul. | Flowering Jun–Aug. |
Habitat | Damp humus in shady forests of Appalachian Mountains, often beneath Rhododendron in acidic soil, also in sphagnous thickets and bogs | In moist, rich humus of mossy coniferous or mixed hardwood forests, swamps, often along cold streams fed by melting snow, prefers high acidic soils |
Elevation | 600–1300 m (2000–4300 ft) | 1500–3000 m (4900–9800 ft) |
Distribution |
GA; KY; MD; NC; NJ; PA; SC; TN; VA; WV
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AK; CO; ID; MT; OR; UT; WA; WY; AB; BC; MB; NL; NT; NU; ON; QC; SK; YT
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Discussion | Listera nipponica Makino, a species similar to L. smallii, occurs in the mountains of Japan. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
In Japan Listera borealis is replaced by L. yatabei Makino, which is nearly identical except for short basal auricles. Listera borealis and L. auriculata are very similar in overall appearance; the ovaries and pedicels in L. borealis are glandular-pubescent, and in L. auriculata they are glabrous. Leaves occur three in a whorl in Listera borealis forma trifolia Lepage. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 26, p. 591. | FNA vol. 26, p. 590. |
Parent taxa | Orchidaceae > subfam. Epidendroideae > tribe Neottieae > subtribe Limodorinae > Listera | Orchidaceae > subfam. Epidendroideae > tribe Neottieae > subtribe Limodorinae > Listera |
Sibling taxa | ||
Synonyms | L. reniformis, Bifolium smallii, Neottia smallii, Ophrys smallii | Neottia borealis, Ophrys borealis |
Name authority | Wiegand: Bull. Torrey Bot. Club 26: 169. (1899) | Morong: Bull. Torrey Bot. Club 20: 31. (1893) |
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