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bog, bog American-laurel, bog-laurel, mountain laurel, pale laurel, swamp, swamp laurel

hairy laurel, hairy mountain-laurel, sandhill laurel

Habit Shrubs erect, to 1 m. Twigs slightly flattened, 2-angled, viscid, glabrous or puberulent in decurrent, ciliolate lines from petiole base. Shrubs spreading to erect, 0.3–0.6(–1.2) m. Twigs terete, viscid, puberulent, densely hispid.
Leaves

opposite;

petiole 0.1–3 mm, glabrous or puberulent (base ciliate);

blade usually oblong to linear, sometimes oval, 1.5–4.5 × 0.3–1.5 cm, margins usually revolute, apex obtuse to acute, abaxial surface puberulent, adaxial glabrate with puberulent bands on either side of midrib, midribs on both surfaces covered with purple, clavate trichomes.

alternate;

petiole 0.1–1 mm, hirsute-puberulent;

blade elliptic to ovate, 0.5–1.4 × 0.1–0.8 cm, margins slightly revolute, apex acute, rounded-apiculate, surfaces usually puberulent, hispid, and stipitate-glandular, rarely glabrous.

Inflorescences

solitary flowers or terminal, corymbiform racemes, 3–8(–17)-flowered.

axillary, scattered along stem, usually solitary flowers, sometimes fascicles or compact racemes, 2–5-flowered.

Pedicels

15–30 mm.

10–15 mm.

Flowers

sepals pale, translucent, white to light pink, ovate, 2.9–4 mm, apex obtuse, surfaces glabrous, margins ciliate;

petals connate their entire lengths, usually rose-purple or pink, rarely white, 9–11 × 12–18 mm, glabrous except puberulent near base abaxially;

filaments 4–5 mm;

style 4.5–7 mm.

sepals tardily deciduous, green, lanceolate, 3–8 mm, apex acute, surfaces puberulent, hispid, stipitate-glandular;

petals connate their entire lengths, pink (rarely white), red near anther pockets, with ring of red spots proximal to pockets, 8–10 × 10–15 mm, usually sparsely hirsute and stipitate-glandular on keels abaxially, puberulent at base adaxially;

filaments 3–4 mm;

style 5–7.5 mm.

Capsules

5-locular, 4–6 × 4–7 mm, glabrous.

5-locular, 2–3.5 × 2–4 mm, sparsely stipitate-glandular.

Seeds

winged, oblong, 1.5–2.2 mm.

not winged, ovoid, 0.2–0.5 mm.

2n

= 48.

= 24.

Kalmia polifolia

Kalmia hirsuta

Phenology Flowering May–Jul. Flowering May–Jul.
Habitat Open bogs, swamps, wet alpine slopes Open sandy savannas, sand hills, and pine barrens
Elevation 0-800 m (0-2600 ft) 0-100 m (0-300 ft)
Distribution
from FNA
CT; MA; ME; MI; MN; NH; NJ; NY; PA; RI; VT; WI; AB; MB; NB; NF; NS; NT; ON; PE; QC; SK [Introduced in Europe (England)]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; SC
[WildflowerSearch map]
[BONAP county map]
Discussion

Kalmia polifolia is very closely related to K. microphylla and there is no general agreement on their taxonomic treatment. The two taxa have different flavonoid profiles and are distinctly separated (S. Liu 1993). The controversial Pacific lowland (Washington to Alaska) entity occidentalis resembles K. polifolia in structure; it is closely related to typical microphylla chemically and is separable from K. polifolia by key characters.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 8, p. 485. FNA vol. 8, p. 483.
Parent taxa Ericaceae > subfam. Ericoideae > Kalmia Ericaceae > subfam. Ericoideae > Kalmia
Sibling taxa
K. angustifolia, K. buxifolia, K. cuneata, K. hirsuta, K. latifolia, K. microphylla, K. procumbens
K. angustifolia, K. buxifolia, K. cuneata, K. latifolia, K. microphylla, K. polifolia, K. procumbens
Synonyms K. glauca Chamaedaphne hirsuta, K. ciliata, Kalmiella hirsuta
Name authority Wangenheim: Schriften Ges. Naturf. Freunde Berlin 8(3): 130, plate 5. 1788 , Walter: Fl. Carol., 138. 1788 ,
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