''Kalmia'' is a genus of about ten species of evergreen

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s from 0.2–5 m tall, in the family Ericaceae. They are native to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

(mainly in the eastern half of the continent) and Cuba. They grow in

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

ic soils, with different species in wet acid bog habitats (''K. angustifolia, K. polifolia'') and dry, sandy soils (''K. ericoides, K. latifolia''). ''Kalmia'' was named by Linnaeus to honour his friend the botanist Pehr Kalm, who collected it in eastern North America during the mid-18th century. Earlier, Mark Catesby saw it during his travels in

Carolina Carolina may refer to: Geography * The Carolinas, the U.S. states of North and South Carolina ** North Carolina, a U.S. state ** South Carolina, a U.S. state * Province of Carolina, a British province until 1712 * Carolina, Alabama, a town in ...

, and after his return to England in 1726, imported seeds. He described it, a costly rarity, in his ''Natural History of Carolina'', as ''Chamaedaphne foliis tini'', that is to say "with leaves like the

Laurustinus ''Viburnum tinus'', the laurustinus, laurustine or laurestine, is a species of flowering plant in the family Adoxaceae, native to the Mediterranean area of Europe and North Africa. ''Laurus'' signifies the leaves' similarities to bay laurel. Des ...

"; the botanist and plant-collector Peter Collinson, who had begged some of the shrub from his correspondent John Custis in Virginia, wrote, when his plants flowered, that "I Really Think it exceeds the Laurus Tinus." Mountain laurel blooms (5940253290)

The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are 2–12 cm long and simple lanceolate. The flowers are white, pink or purple, in corymbs of 10-50, reminiscent of

Rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nati ...

flowers but flatter, with a star-like calyx of five conjoined

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s; each flower is 1–3 cm diameter. The fruit is a five-lobed capsule, which splits to release the numerous small seeds. The foliage contains grayanotoxins, a group of closely related

neurotoxin Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature ner ...

s named after ''Leucothoe grayana'', native to Japan, so it is toxic if eaten, with sheep being particularly prone to poisoning, hence the name lambkill used for some of the species. Other names for Kalmia, particularly ''Kalmia angustifolia,'' are sheep-laurel, lamb-kill, calf-kill, kill-kid, and sheep-poison,Natural History Education, Science, Technology
regarding alternate names, accessed March 30, 2007. which may be written with or without the hyphen. (See species list below.) "Kid" here refers to a young goat, not a human child, but the foliage and twigs are toxic to humans as well. It has also been called

spoonwood Spoonwood is a common name for two plants: *''Kalmia latifolia'', a North American plant known as mountain laurel and numerous other names emphasizing its poisonous nature, such as lambkill, kill-kid, and calf-kill. *''Trichilia havanensis ''Tri ...

because Kalm was told by Dutch settlers of North America that Native Americans made spoons from the wood. Given its toxicity, this may be folklore rather than scientific fact. Kalmias are popular garden shrubs, grown for their decorative flowers. They should not be planted where they are accessible to livestock due to the toxicity. ''Kalmia'' species are used as food plants by the larvae of some

lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

n species including '' Coleophora kalmiella'' which feeds exclusively on ''Kalmia''.

Species

Species (and infraspecific taxa) listed by The Plant List as "Accepted": * '' Kalmia angustifolia'' L. - Sheep-laurel, lambkill * ''

Kalmia buxifolia ''Kalmia buxifolia'' is a species of flowering plant in the family Ericaceae known by the common name sandmyrtle, or sand-myrtle. It is native to the mid-Atlantic and southeastern United States, where it has a disjunct distribution, occurring in ...

'' (Bergius) Gift & Kron - Sandmyrtle * ''

Kalmia carolina ''Kalmia'' is a genus of about ten species of evergreen shrubs from 0.2–5 m tall, in the family Ericaceae. They are native to North America (mainly in the eastern half of the continent) and Cuba. They grow in acidic soils, with different spe ...

'' Small - Carolina mountain-laurel * ''

Kalmia cuneata ''Kalmia cuneata'' is a species of flowering plant in the heath family known by the common name whitewicky, sometimes spelled white-wicky or white wicky. It is native to the eastern United States, where it occurs only in North Carolina and South C ...

'' Michx. - Whitewicky * ''

Kalmia ericoides ''Kalmia'' is a genus of about ten species of evergreen shrubs from 0.2–5 m tall, in the family Ericaceae. They are native to North America (mainly in the eastern half of the continent) and Cuba. They grow in acidic soils, with different spe ...

'' C.Wright ex Griseb. - Cuban kalmia ** ''Kalmia ericoides'' var. ''aggregata'' (Small) Ebinger * '' Kalmia hirsuta'' Walter - Hairy mountain-laurel * '' Kalmia latifolia'' L. - Lambkill ** ''Kalmia latifolia'' f. ''alba'' (Mouill.) Rehder ** ''Kalmia latifolia'' f. ''fuscata'' (Rehder) Rehder ** ''Kalmia latifolia'' f. ''obtusata'' (Rehder) Rehder ** ''Kalmia latifolia'' f. ''polypetala'' (G.Nicholson) Rehder * ''

Kalmia microphylla ''Kalmia microphylla'', known as alpine laurel, bog laurel, swamp-laurel, western bog-laurel or western laurel, is a species of ''Kalmia'' of the family Ericaceae. It is native to North America and can be found throughout the western US and weste ...

'' (Hook.) A.Heller - Alpine laurel, alpine bog-laurel, alpine mountain-laurel ** ''Kalmia microphylla'' subsp. ''occidentalis'' (Small) Roy L.Taylor & MacBryde * ''

Kalmia polifolia ''Kalmia polifolia'', previously known as ''Kalmia glauca'' and commonly called bog laurel, swamp laurel, or pale laurel, is a perennial evergreen shrub of cold acidic bogs, in the family Ericaceae. It is native to north-eastern North America, f ...

'' Wangenh. - Bog kalmia, bog-laurel * ''

Kalmia simulata ''Kalmia'' is a genus of about ten species of evergreen shrubs from 0.2–5 m tall, in the family Ericaceae. They are native to North America (mainly in the eastern half of the continent) and Cuba. They grow in acidic soils, with different spec ...

'' (Britton & M.Wilson) Southall ''

Kalmia procumbens ''Kalmia procumbens'', commonly known as alpine azalea or trailing azalea, is a dwarf shrub of high mountain regions of the Northern Hemisphere that usually grows no more than tall. Originally named by Linnaeus as ''Azalea procumbens'', it is al ...

'' is a widely accepted member of this genus, though it is the only species in the genus ''Loiseleuria'' according to The Plant List. The related ''

Kalmiopsis ''Kalmiopsis'' is a small genus of flowering plants in the family Ericaceae. Species It contains two species, which are endemic to Oregon in the United States.Kalmiopsis leachiana ''Kalmiopsis leachiana'', commonly referred to as kalmiopsis, is a rare flowering plant endemic to the Siskiyou Mountains of southwest Oregon, where it is specially protected in the Kalmiopsis Wilderness reserve. It was discovered in 1930 by L ...

'' and '' K. fragrans'') is a rare shrub endemic to southwest Oregon. File:FFH-Gebiet "Altwarmbüchener Moor" (cropped).JPG, ''Kalmia angustifolia'' File:Kalmia buxifolia NRCS-2.jpg, ''Kalmia buxifolia'' File:Mountain Laurel - Flickr - treegrow (13).jpg, ''Kalmia latifolia'' File:Western Bog Laurel (cropped).jpg, ''Kalmia microphylla'' File:Kalmia polifolia.jpg, ''Kalmia polifolia''

Fossil record

Fossil leaves of †''Kalmia saxonica'' have been described from the Lower Miocene of Brandis, Germany and Bełchatów, Poland, †Kalmia marcodurensis'' have been described from the Lower Miocene of Bitterfeld, Germany. In the Late Tertiary ''Kalmia'' was associated with coal-forming vegetation occurring as a component of the vegetation of bush swamps together with '' Cyrilla'' and other shrubs. Among recent species '' Kalmia angustifolia'' is most similar to †''Kalmia saxonica'' in respect of morphology, while '' Kalmia latifolia'' has a very similar epidermal structure. These two extant species grow in the eastern part of

from ( Quebec to Florida) on acid swampy or marshy soils. Acta Palaeobotanica - Supplementum No. 3 - New Fossil Floras from Neogene Deposits in the Bełchatów Lignite Mine by Grzegor Worobiec - Polish Academy of Sciences, W. Szafer Institute of Botany, Krakow 2003

Bibliography

Books

* Jaynes, Richard A., 1997: Kalmia, mountain laurel and related species, Timber Press, Portland, Oregon, U.S.A. * Huebbers, Karl-Heinz and Westhoff, Julia,2020 : Fascynujące kalmie (Fascinating Kalmie) published by Plantin, Krakow, Poland ISBN: 978-83-956964-0-4

References

External links

European Kalmia SocietyKalmia.info: German Kalmia hybridizersPieris.eu: Info about ''Kalmia latifolia''
{{Taxonbar, from=Q1427635 Ericaceae genera Taxa named by Carl Linnaeus