The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

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
from FNA
GA; KY; MD; NC; NJ; PA; SC; TN; VA; WV
[WildflowerSearch map]
from FNA
AK; CO; ID; MT; OR; UT; WA; WY; AB; BC; MB; NL; NT; NU; ON; QC; SK; YT
[WildflowerSearch map]
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
L. auriculata, L. australis, L. borealis, L. caurina, L. convallarioides, L. cordata, L. ovata
L. auriculata, L. australis, L. caurina, L. convallarioides, L. cordata, L. ovata, L. smallii
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)
Web links