''Coleus scutellarioides'', commonly known as coleus, is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...
in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Lamiaceae
The Lamiaceae ( )
or Labiatae are a family of flowering plants commonly known as the mint, deadnettle or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil, mint, rosemary, sage, savory ...
(the mint or deadnettle family),
native
Native may refer to:
People
* Jus soli, citizenship by right of birth
* Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory
** Native Americans (disambiguation)
In arts and entert ...
to southeast Asia through to Australia. Typically growing to tall and wide, it is a bushy, woody-based
evergreen
In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...
perennial
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widel ...
, widely grown for the highly decorative
variegated
Variegation is the appearance of differently coloured zones in the leaves and sometimes the stems and fruit of plants. Species with variegated individuals are sometimes found in the understory of tropical rainforests, and this habitat is the ...
leaves found in cultivated varieties. Another common name is painted nettle, reflecting its relationship to deadnettles (''
Lamium
''Lamium'' (dead-nettles) is a genus of about 30 species of flowering plants in the family Lamiaceae, of which it is the type genus. They are all herbaceous plants native to Europe, Asia, and northern Africa, but several have become very successf ...
'' species), which are in the same family. (True nettles and their close kin are in the distant family
Urticaceae
The Urticaceae are a family, the nettle family, of flowering plants. The family name comes from the genus ''Urtica''. The Urticaceae include a number of well-known and useful plants, including nettles in the genus ''Urtica'', ramie (''Boehmeri ...
.) The
synonyms
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are ...
''Coleus blumei'', ''Plectranthus scutellarioides'' and ''Solenostemon scutellarioides'' are also widely used for this species.
Description
''Coleus scutellarioides'' is an upright
annual
Annual may refer to:
*Annual publication, periodical publications appearing regularly once per year
** Yearbook
** Literary annual
*Annual plant
*Annual report
*Annual giving
*Annual, Morocco, a settlement in northeastern Morocco
*Annuals (band), ...
or short-lived perennial plant. It may be as much as tall, with well-branched, more-or-less four-sided stems. Shorter, more trailing forms have sometimes been described as separate species, under names such as ''Coleus pumilus'' or ''Solenostemon pumilus'', but are all now considered part of the very variable ''C. scutellarioides''. The species is extremely variable in the colour and shape of the leaves. They are somewhat fleshy, varying in size from long by wide, generally
ovate
Ovate may refer to:
* Ovate (egg-shaped) leaves, tepals, or other botanical parts
*Ovate, a type of prehistoric stone hand axe
*Ovates, one of three ranks of membership in the Welsh Gorsedd
*Vates
In modern English, the nouns vates () and ova ...
in shape, and borne on petioles (stalks) from long. The leaf margin is divided to a variable degree. Hairs are present on both sides of the leaf.
The
inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...
is borne on the end of a stem and, like the leaves, is very variable in size; it may be up to long, with few or many flowers. The
calyx
Calyx or calyce (plural "calyces"), from the Latin ''calix'' which itself comes from the Ancient Greek ''κάλυξ'' (''kálux'') meaning "husk" or "pod", may refer to:
Biology
* Calyx (anatomy), collective name for several cup-like structures ...
is bell-shaped, initially only long, but lengthening to when in fruit. The bluish-purple
petal
Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usuall ...
s are joined to form a typical two-lipped labiate flower, long. The
stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the fila ...
s are joined for about half their length and are covered by the upper lip of the flower. The fruit is described as a "nutlet", and is black, about long.
Pigmentation
The leaves of the wild species may be somewhat variegated, but this has been developed to an extreme degree in cultivated varieties, whose leaves may include one or more shades of green, white, cream, yellow, pink, red, maroon and dark purple. Green coloration is due to the amount of
chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to ...
present in the chloroplasts in the leaves. Red, purple, pink, and orange colors are due to
anthocyanins
Anthocyanins (), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart gave the name Anthokyan to a chemical com ...
– water-soluble, flavonoid biosynthetic pigments, found in the foliage in addition to chlorophyll. The increase in anthocyanin production is accompanied by a decrease in chlorophyll production. The production of anthocyanins and chlorophyll is affected by light levels; the more light is present, the more anthocyanins are produced, with an inverse relationship to the production of chlorophyll. Anthocyanins are created inside the cell and facilitate
photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in ...
in leaves that are exposed to very intense or prolonged sunlight by providing protection from damage caused by
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
light. Some coleus cultivars over-produce anthocyanins and under-produce chlorophyll to the extent that optimal growth is prevented.
Taxonomy
The species was first described by
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, ...
in 1763, as ''Ocimum scutellarioides''. The genus '' Ocimum'' is best known for ''
Ocimum basilicum
Basil (, ; ''Ocimum basilicum'' , also called great basil, is a culinary herb of the family Lamiaceae (mints). It is a tender plant, and is used in cuisines worldwide. In Western cuisine, the generic term "basil" refers to the variety also k ...
'', sweet basil. The
specific epithet
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...
George Bentham
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
transferred it to the genus ''Coleus'' as ''Coleus scutellarioides'' in 1830, and in 1832 also described ''Coleus blumei'', now regarded as just a variant of this species. Placement in the genus ''Coleus'' led to the name "coleus", still widely used by horticulturalists and gardeners, and now treated as a
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...
for this species. It was transferred to ''Solenostemon'' by Leslie E. W. Codd in 1975.
A major
phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...
study of the subtribe Plectranthinae in 2018 showed that the genus ''Plectranthus'', as then circumscribed, was not
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...
, and the authors proposed re-instating ''Coleus'', then wholly submerged in ''Plectranthus''. A summary cladogram for the subtribe Plectranthinae, based on the 2018 study, was published in 2019, along with names in ''Coleus'' for all the species recognized in that genus. In the version of the cladogram below, the three genera that formed part of ''Plectranthus'' s.l. are highlighted.
Distribution and habitat
''Coleus scutellarioides'' is native from southeast Asia through to Australia (the Bismarck Archipelago, Borneo, Cambodia, Southeast China, Java, Laos, the Lesser Sunda Islands, Peninsular Malaysia, Maluku, Myanmar, Nansei-shoto, New Guinea, Northern Territory, Philippines, Queensland, the Solomon Islands, Sulawesi, Sumatra, Taiwan, Thailand, Vietnam, and Western Australia). It is cultivated worldwide and may be naturalized in other tropical regions. In its native habitat, it is found at elevations of , where it flowers and fruits throughout the year. It is winter hardy to
USDA Zone
A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most wide ...
s 10–11.
Cultivation
History
The species was first introduced into Europe from Java in 1851 by a Dutch horticulturalist. At this time, there were few leaf colors and shapes. A wider variety was available by 1877, when the American William Bull offered seeds at 43 US cents each. However, by selecting for seed production, early flowering was inadvertently favored, and leaf color also declined in intensity. Coleus breeding revived in the early 1940s, and by the 1980s, the availability of an improved range of cultivars led to coleus becoming the tenth most important bedding crop in the US. More recently, vegetative propagation has enabled cultivars with novel leaf colors and shapes to be offered for sale. Plants with trailing as well as upright habits are now available.
cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...
s typically show sharp contrasts between their colors; particular leaves may be several shades of green, pink, yellow, "black" (a very dark purple), maroon, cream, white, and red (somewhat resembling the unrelated ''
Caladium
''Caladium'' is a genus of flowering plants in the family Araceae. They are often known by the common name elephant ear (which they share with the closely related genera '' Alocasia'', '' Colocasia'', and '' Xanthosoma''), heart of Jesus, and ...
''). The leaf shape also varies from broadly ovate to more narrowly lanceolate. The leaf margins may have small or large teeth or be wavy, as may the whole leaf. New cultivars with different leaf shapes and color combinations are constantly being created.
AGM cultivars
The following cultivars have gained the
Royal Horticultural Society
The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity.
The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nor ...
's
Award of Garden Merit
The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions.
History
The Award of Garden Merit ...
In cultivation, plants grow well in moist well-drained soil, and are usually tall, though some may grow as tall as . Coleus are grown as
ornamental plant
Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...
s. They are heat-tolerant, but they do less well in full sun in subtropical areas than in the shade. In areas without freezing temperatures, plants can usually be kept as perennials if well managed. In colder areas, they are often grown as annuals, since the plants are not hardy and become leggy with age. In bright, hot areas, the colors of the plant are typically more intense in shade than in full sun, and the plants require less water there. Coleus also make low-maintenance
houseplant
A houseplant, sometimes known as a pot plant, potted plant, or an indoor plant, is an ornamental plant that is grown indoors. As such, they are found in places like residences and offices, mainly for decorative purposes. Common houseplants are us ...
s, and can often be propagated by clipping a piece of stem just below the leaves and putting the stem in water to root. Young inflorescences may be removed to keep plants more compact.
Propagation
There are two ways to
propagate
Propagation can refer to:
*Chain propagation in a chemical reaction mechanism
* Crack propagation, the growth of a crack during the fracture of materials
*Propaganda, non-objective information used to further an agenda
*Reproduction, and other form ...
coleus. Seeds are inexpensive and easily obtainable, though named cultivars do not come true from seeds. To germinate seeds, simply sprinkle seeds on the soil surface and press down. Seeds require light to germinate, so should not be covered. They may be kept moist by growing in a container covered with plastic, or by misting seeds daily. Sprouts can show color in as little as two weeks. Alternatively,
cutting
Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed force.
Implements commonly used for wikt:cut, cutting are the knife and saw, or in medicine and science the scal ...
s can be taken. Cuttings root readily in plain water, without the addition of rooting hormone (although it is still beneficial).
Diseases
The
downy mildew
Downy mildew refers to any of several types of oomycete microbes that are obligate parasites of plants. Downy mildews exclusively belong to the Peronosporaceae family. In commercial agriculture, they are a particular problem for growers of cruc ...
''Peronospora'' sp. makes leaves brownish and can also cause leaf curling and twisting. It is harder to control this mildew on stems compared to leaves. Another disease is
impatiens necrotic spot virus
''Impatiens necrotic spot orthotospovirus'' (INSV) is a plant pathogenic virus of the order ''Bunyavirales''. It was originally believed to be another strain of '' Tomato spotted wilt virus,'' but genetic investigations revealed them to be separ ...
which causes brown or yellow spots on leaves, rings, black or brown stem discoloration, and brown leaf veins, ultimately resulting in plant death. The disease is spread by an insect called a
thrips
Thrips (order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...
''Coleus scutellarioides'', under the name ''Coleus blumei'', has been reported to have very mild relaxing and/or hallucinogenic effects when consumed. The effects of the plant have not been scientifically explored in great detail, but the plant is known to have been used by the Mazatec people of southern Mexico for its mind-altering effects.
Gallery
Coleus scutellarioides, inflorescence.jpg, Inflorescence
Coleus tree.jpg, Cultivar grown as a short standard