Kalmia angustifolia
Kalmia microphylla
lambkill, sheep American-laurel, sheep-laurel
alpine laurel, bog laurel, swamp laurel, western bog-laurel, western swamp laurel
usually in whorls of 3, rarely alternate or opposite;
petiole 6–16 mm, usually puberulent;
blade oblong to elliptic-lanceolate, 1.5–8 × 0.5–2.5 cm, margins usually plane, apex obtuse to acute, usually apiculate, abaxial surface glabrous or puberulent, sometimes stipitate-glandular, adaxial lightly puberulent (hairs white, to 0.1 mm), sometimes glabrescent, midrib puberulent.
opposite;
petiole absent or 0.1–2 mm, glabrous or puberulent;
blade ovate or oval to broadly elliptic or lanceolate, 1.5–4 × 0.3–1.2(–1.8) cm, margins plane to slightly revolute, apex obtuse to acute, abaxial surface puberulent, adaxial glabrous or sparsely puberulent towards base, midribs of both surfaces without purple, stipitate trichomes.
axillary near distal end, corymbiform racemes, 4–12-flowered.
solitary flowers or terminal, corymbiform racemes, (3–)6–12-flowered.
5–20 mm.
10–30 mm.
sepals usually green, sometimes reddish apically or throughout, ovate, 2–2.8 mm, apex usually acuminate, surfaces puberulent;
petals connate nearly their entire lengths, usually reddish purple to pink, rarely white or bluish pink, usually deeper colored near anther pockets and with ring of red to purple spots just proximal to pockets, 7.5–9.5 × 6–13 mm, abaxial surface puberulent, adaxial glabrous, puberulent toward base;
filaments 2.5–3.5 mm;
style 3.5–4.5 mm.
sepals light pink, pink, or light green, ovate, 2.7–3.6 mm, apex obtuse, surfaces glabrous, margins ciliate;
petals connate ca. 1/2 their lengths, usually rose-purple, rarely white, 7–9 × 8–20 mm, glabrous, puberulent near base abaxially;
filaments 3–4.5 mm;
style 4.5–7 mm.
5-locular, 2–3.5 × 3–5 mm, puberulent, stipitate-glandular.
5-locular, 3.5–6 × 4–7 mm, glabrous.
winged, obovoid, 0.6–1 mm.
winged, oblong, 0.5–1.4 mm.
= 24.
= 24.
Kalmia angustifolia
Kalmia microphylla
Varieties 2 (2 in the flora).
The two varieties of Kalmia angustifolia are largely separate geographically and show different flavonoid profiles (S. Liu 1993). Southeastern Virginia has long been known as a region of overlap of these two entities; field and herbarium work (B. A. Sorrie and A. S. Weakley, unpubl.) has demonstrated that the two taxa retain their distinctiveness and that hybrids are rare. Sorrie and Weakley concluded that the two should be treated as separate species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 2 (2 in the flora).
Kalmia microphylla is highly variable and has been treated as two species (J. K. Small 1914), two subspecies (R. L. Taylor and B. MacBryde 1978), or two varieties (J. E. Ebinger 1974). A flavonoid study (S. Liu 1993) indicated that the Pacific lowland (from Washington to Alaska) var. occidentalis populations are hardly separable from the alpine var. microphylla populations. The flavonoid data cited in support of combining K. microphylla and K. occidentalis are unpublished and impossible to judge. In any case, one would not expect varieties to necessarily differ chemically; the morphological and ecological differences seem sufficient.
The two varieties of Kalmia microphylla are generally distinct; var. microphylla is common in alpine meadows of western North America from California through the Rocky Mountains into northern Canada and Alaska. The elevations at which it is found range from an average 2500 meters (1500–3500 m) in California to an average 1700 meters (900–2200 m) in Alberta, British Columbia, and Washington. Variety occidentalis, in contrast, is always encountered growing below 900 meters, being common in coastal areas and islands off the coast of Alaska and British Columbia. These two varieties are known to hybridize (J. E. Ebinger 1974), and the hybrids are highly fertile and set large quantities of viable seed (R. A. Jaynes 1988).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Calyces densely stipitate-glandular; leaf blade surfaces glabrous or scattered, stipitate-glandular trichomes. | var. angustifolia |
1. Calyces usually not stipitate-glandular; leaf blade surfaces densely puberulent abaxially, usually not stipitate-glandular. | var. carolina |
1. Leaf blades ovate or oval to broadly elliptic, 1.5 (-2.5) cm, to 2.5 times as long as wide; calyces 5-7 mm diam. | var. microphylla |
1. Leaf blades lanceolate, 2-4 cm, 2.5-4 times as long as wide; calyces 7-10 mm diam. | var. occidentalis |
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