Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar ornamentals, such as Alcea (hollyhock), Malva (mallow) and Lavatera (tree mallow). The largest genera in terms of number of species include Hibiscus (300 species), Sterculia (250 species), Dombeya (250 species), Pavonia (200 species) and Sida (200 species).
|Least mallow, Malva parviflora|
The circumscription of the Malvaceae is controversial. The traditional Malvaceae sensu stricto comprise a very homogeneous and cladistically monophyletic group. Another major circumscription, Malvaceae sensu lato, has been more recently defined on the basis that molecular techniques have shown the commonly recognised families Bombacaceae, Tiliaceae, and Sterculiaceae, which have always been considered closely allied to Malvaceae s.s., are not monophyletic groups. Thus, the Malvaceae can be expanded to include all of these families so as to compose a monophyletic group. Adopting this circumscription, the Malvaceae incorporate a much larger number of genera.
This article is based on the second circumscription, as presented by the Angiosperm Phylogeny Website. The Malvaceae s.l. (hereafter simply "Malvaceae") comprise nine subfamilies. A tentative cladogram of the family is shown below. The diamond denotes a poorly supported branching (<80%).
It is important to point out the relationships between these subfamilies are still either poorly supported or almost completely obscure. There are continuing disagreements over the correct circumscription of these subfamilies, including the preservation of the family, Bombacaceae. The circumscription of the family may change dramatically as new studies are published.
If looking for information about the traditional Malvaceae s.s., we recommend referring to Malvoideae, the subfamily that approximately corresponds to that group.
The relationships between the "core Malvales" families used to be defined on the basis of shared "malvean affinities." These included the presence of malvoid teeth, stems with mucilage canals, and stratified wedge-shaped phloem. These affinities were problematic because they were not always shared within the core families. Later studies revealed more unambiguous synapomorphies within Malvaceae s.l.. Synapomorphies identified within Malvaceae s.l. include the presence of tile cells, trichomatous nectaries, and an inflorescence structure called a bicolor unit. Tile cells consist of vertically positioned cells interspersed between and dimensionally similar to procumbent ray cells. Evidence of Malvean wood fossils have confirmed their evolutionary link in Malvaceae s.l., as well explained their diverse structures. Flowers of Malvaceae s.l. exhibit nectaries consisting of densely arranged multicellular hairs resembling trichomes. In most of Malvaceae s.l., these trichomatous nectaries are located on the inner surface of the sepals, but flowers of the subfamily, Tiliodeae, also have present nectaries on the petals. Malvean flowers also share a unifying structure known as a bicolor unit, named for its initial discovery in the flowers of Theobroma bicolor. The bicolor unit consists of an ordered inflorescence with determinate cymose structures. The inflorescence can branch off the main axis, creating separate orders of the flowers, with the main axis developing first. Bracts on the peduncle subtend axillary buds that become these lateral stalks. One bract within this whorl is a sterile bract. The bicolor unit is a variable structure in complexity, but the presence of fertile and sterile bracts is a salient character.
The English common name 'mallow' (also applied to other members of Malvaceae) comes from Latin malva (also the source for the English word "mauve"). Malva itself was ultimately derived from the word for the plant in ancient Mediterranean languages. Cognates of the word include Ancient Greek μαλάχη (malákhē) or μολόχη (molókhē), Modern Greek μολόχα (molóha), modern Arabic: ملوخية (mulukhiyah) and modern Hebrew: מלוחיה (molokhia).
Leaves are generally alternate, often palmately lobed or compound and palmately veined. The margin may be entire, but when dentate, a vein ends at the tip of each tooth (malvoid teeth). Stipules are present. The stems contain mucous canals and often also mucous cavities. Hairs are common, and are most typically stellate.. Stems of Bombacoideae are often covered in thick prickles.
The flowers are commonly borne in definite or indefinite axillary inflorescences, which are often reduced to a single flower, but may also be cauliflorous, oppositifolious, or terminal. They often bear supernumerary bracts in the structure of a bicolor unit. They can be unisexual or bisexual, and are generally actinomorphic, often associated with conspicuous bracts, forming an epicalyx. They generally have five valvate sepals, most frequently basally connate, with five imbricate petals. The stamens are five to numerous, and connate at least at their bases, but often forming a tube around the pistils. The pistils are composed of two to many connate carpels. The ovary is superior, with axial placentation, with capitate or lobed stigma. The flowers have nectaries made of many tightly packed glandular hairs, usually positioned on the sepals.
Self-pollination is often avoided by means of protandry. Most species are entomophilous (pollinated by insects). Bees from the Emphorini tribe of the Apidae (including Ptilothrix, Diadasia, and Melitoma) are known to specialize on the plants.
A number of species are pests in agriculture, including Abutilon theophrasti and Modiola caroliniana, and others that are garden escapes. Cotton (four species of Gossypium), kenaf (Hibiscus cannabinus), cacao (Theobroma cacao), kola nut (Cola spp.), and okra (Abelmoschus esculentus) are important agricultural crops. The fruit and leaves of baobabs are edible, as is the fruit of the durian. A number of species, including Hibiscus syriacus, Hibiscus rosa-sinensis and Alcea rosea are garden plants.
Abutilon is a large genus of flowering plants in the mallow family, Malvaceae. It is distributed throughout the tropics and subtropics of the Americas, Africa, Asia, and Australia. General common names include Indian mallow and velvetleaf; ornamental varieties may be known as room maple, parlor maple, or flowering maple.
The genus name is an 18th-century New Latin word that came from the Arabic ’abū-ṭīlūn (أبو طيلون), the name given by Avicenna to this or a similar genus.The type species is Abutilon theophrasti. Several species formerly placed in Abutilon, including the cultivated species and hybrids commonly known as "flowering maples", have recently (2012, 2014) been transferred to the new genus Callianthe.Adansonia
Adansonia is a genus of deciduous trees known as baobabs. They are found in arid regions of Madagascar, mainland Africa, Arabia, and Australia. The generic name honours Michel Adanson, the French naturalist and explorer who described Adansonia digitata.In the early 21st century, baobabs in southern Africa began to die off rapidly from a cause yet to be determined. Scientists believe it is unlikely that disease or pests were able to kill many trees so rapidly, while some speculated that the die-off was a result of dehydration from global warming.Alcea
Alcea is a genus of about 60 species of flowering plants in the mallow family Malvaceae, commonly known as the hollyhocks. They are native to Asia and Europe. The single species of hollyhock from the Western Hemisphere, the streambank wild hollyhock, belongs to a different genus.Althaea (plant)
Althaea is a genus of 6–12 species of perennial herbs native to Europe, North Africa and western Asia. It includes Althaea officinalis, also known as the marshmallow plant, whence the fluffy confection got its name. They are found on the banks of rivers and in salt marshes, preferring moist, sandy soils. The stems grow to 1–2 m tall, and flower in mid summer. The leaves are palmately lobed with 3–7 lobes. Althaea species are used as food plants by the larvae of some Lepidoptera species including Bucculatrix quadrigemina.Bombacaceae
Bombacaceae were long recognised as a family of flowering plants or Angiospermae. The family name was based on the type genus Bombax. As is true for many botanical names, circumscription and status of the taxon has varied with taxonomic point of view, and currently the preference is to transfer most of the erstwhile family Bombacaceae to the subfamily Bombacoideae within the family Malvaceae in the order Malvales. The rest of the family were transferred to other taxa, notably the new family Durionaceae. Irrespective of current taxonomic status, many of the species originally included in the Bombacaceae are of considerable ecological, historical, horticultural, and economic importance, such as balsa, kapok, baobab and durian.Ceiba
Ceiba is a genus of trees in the family Malvaceae, native to tropical and subtropical areas of the Americas (from Mexico and the Caribbean to N Argentina) and tropical West Africa. Some species can grow to 70 m (230 ft) tall or more, with a straight, largely branchless trunk that culminates in a huge, spreading canopy, and buttress roots that can be taller than a grown person. The best-known, and most widely cultivated, species is Kapok, Ceiba pentandra, one of several trees called kapok.
Ceiba species are used as food plants by the larvae of some Lepidoptera (butterfly and moth) species, including the leaf-miner Bucculatrix ceibae, which feeds exclusively on the genus.
Recent botanical opinion incorporates Chorisia within Ceiba and puts the genus as a whole within the family Malvaceae.Corchorus
Corchorus is a genus of about 40–100 species of flowering plants in the family Malvaceae, native to tropical and subtropical regions throughout the world.Different common names are used in different contexts, with jute applying to the fiber produced from the plant, and mallow-leaves for the leaves used as a vegetable.Gossypium
Gossypium is a genus of flowering plants in the tribe Gossypieae of the mallow family, Malvaceae from which cotton is harvested. It is native to tropical and subtropical regions of the Old and New Worlds. There are about 50 Gossypium species, making it the largest genus in the tribe Gossypieae and new species continue to be discovered. The name of the genus is derived from the Arabic word goz, which refers to a soft substance.Cotton is the primary natural fibre used by modern humans. Where cotton is cultivated it is a major oilseed crop and a main protein source for animal feed. Cotton is thus of great importance for agriculture, industry and trade, especially for tropical and subtropical countries in Africa, South America and Asia. Consequently, the genus Gossypium has long attracted the attention of scientists.
The origin of the genus Gossypium is dated to around 5–10 million years ago. Gossypium species are distributed in arid to semiarid regions of the tropics and subtropics. Generally shrubs or shrub-like plants, the species of this genus are extraordinarily diverse in morphology and adaptation, ranging from fire-adapted, herbaceous perennials in Australia to trees in Mexico.Cultivated cottons are perennial shrubs most often grown as annuals. Plants are 1–2 m high in modern cropping systems, sometimes higher in traditional, multiannual cropping systems, now largely disappearing. The leaves are broad and lobed, with three to five (or rarely seven) lobes. The seeds are contained in a capsule called a "boll", each seed surrounded by fibres of two types. These fibres are the more commercially interesting part of the plant and they are separated from the seed by a process called ginning. At the first ginning, the longer fibres, called staples, are removed and these are twisted together to form yarn for making thread and weaving into high quality textiles. At the second ginning, the shorter fibres, called "linters", are removed, and these are woven into lower quality textiles (which include the eponymous Lint). Commercial species of cotton plant are G. hirsutum (>90% of world production), G. barbadense (3–4%), G. arboreum and G. herbaceum (together, 2%). Many varieties of cotton have been developed by selective breeding and hybridization of these species. Experiments are ongoing to cross-breed various desirable traits of wild cotton species into the principal commercial species, such as resistance to insects and diseases, and drought tolerance. Cotton fibres occur naturally in colours of white, brown, green, and some mixing of these.
Most wild cottons are diploid, but a group of five species from America and Pacific islands are tetraploid, apparently due to a single hybridization event around 1.5 to 2 million years ago. The tetraploid species are G. hirsutum, G. tomentosum, G. mustelinum, G. barbadense, and G. darwinii.Hibiscus
Hibiscus is a genus of flowering plants in the mallow family, Malvaceae. The genus is quite large, comprising several hundred species that are native to warm temperate, subtropical and tropical regions throughout the world. Member species are renowned for their large, showy flowers and those species are commonly known simply as "hibiscus", or less widely known as rose mallow. There are also names for hibiscus such as hardy hibiscus, rose of sharon, and tropical hibiscus.
The genus includes both annual and perennial herbaceous plants, as well as woody shrubs and small trees. The generic name is derived from the Greek name ἰβίσκος (hibiskos) which Pedanius Dioscorides gave to Althaea officinalis (c. 40–90 AD).Several species are widely cultivated as ornamental plants, notably Hibiscus syriacus and Hibiscus rosa-sinensis.A tea made from hibiscus flowers is known by many names around the world and is served both hot and cold. The beverage is known for its red colour, tart flavour, and vitamin C content.Malva
Malva is a genus of about 25–30 species of herbaceous annual, biennial, and perennial plants in the family Malvaceae (of which it is the type genus), one of several closely related genera in the family to bear the common English name mallow. The genus is widespread throughout the temperate, subtropical and tropical regions of Africa, Asia and Europe.The leaves are alternate, palmately lobed. The flowers are from 0.5–5 cm diameter, with five pink, lilac, purple or white petals.
A number of species, previously considered to belong to Lavatera, have been moved to Malva.Malvales
The Malvales are an order of flowering plants. As circumscribed by APG II-system, the order includes about 6000 species within 9 families. The order is placed in the eurosids II, which are part of the eudicots.
The plants are mostly shrubs and trees; most of its families have a cosmopolitan distribution in the tropics and subtropics, with limited expansion into temperate regions. An interesting distribution occurs in Madagascar, where three endemic families of Malvales (Sphaerosepalaceae, Sarcolaenaceae and Diegodendraceae) occur.
Many species of Malvaceae sensu lato are known for their wood, with that of Ochroma (balsa) being known for its lightness, and that of Tilia (lime, linden, or basswood) as a popular wood for carving. Fruit of the cacao tree (Theobroma cacao) are used as an ingredient for chocolate. Kola nuts (genus Cola) are notable for their high content of caffeine and, in past, were commonly used for preparing of various cola drinks. Other well-known members of Malvales in the APG II sense are daphnes, hibiscus, hollyhocks, okra, baobab trees, cotton, and kapok.Malvoideae
Malvoideae is a botanical name at the rank of subfamily, which includes in the minimum the genus Malva. It was first used by Burnett in 1835, but was not much used until recently, where, within the framework of the APG System, which unites the families Malvaceae, Bombacaceae, Sterculiaceae and Tiliaceae of the Cronquist system, the aggregate family Malvaceae is divided into 9 subfamilies, including Malvoideae. The Malvoideae of Kubitzki and Bayer includes 4 tribes:-
Malveae (Abutilon, Alcea, Malva, Sidalcea etc.)
Gossypieae (Gossypium, the cottons etc.)
Hibisceae (Hibiscus etc.)
- and two unplaced genera:-
HowittiaBaum et al. have a wider concept (cladistically, all those plants more closely related to Malva sylvestris than to Bombax ceiba) of Malvoideae, which includes additionally the tribe Matisieae (three genera of Neotropical trees) and the genera Lagunaria, Camptostemon, Pentaplaris and Uladendron.Ochroma
Ochroma is a genus of flowering plants in the mallow family, Malvaceae, containing the sole species Ochroma pyramidale, commonly known as the balsa tree. It is a large, fast-growing tree that can grow up to 30 m tall. Balsa wood is a very lightweight material with many uses. Balsa trees are native to southern Brazil and northern Bolivia, up to southern Mexico.Sensu
Sensu is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular concept, but it also appears in expressions that indicate the convention or context of the usage.Sterculia
Sterculia is a genus of flowering plants in the mallow family, Malvaceae: subfamily Sterculioideae (previously placed in the now obsolete Sterculiaceae). Members of the genus are colloquially known as tropical chestnuts. The scientific name is taken from Sterculius of Roman mythology, who was the god of manure; this is in reference to the unpleasant aroma of the flowers of this genus (e.g. Sterculia foetida). Sterculia may be monoecious or dioecious, and flowers unisexual or bisexual.
Sterculia species are food plants for the larvae of some Lepidoptera species including the leaf miner Bucculatrix xenaula, which feeds exclusively on this genus. Gum karaya is extracted from Sterculia species, and is used as a thickener and emulsifier in foods, as a laxative, and as a denture adhesive. In India, this is sourced from: Gujarat, Maharashtra, Madras, Madhya Pradesh and Chhota Nagpur.Sterculiaceae
Sterculiaceae was a family of flowering plants: based on the genus Sterculia. Genera are now placed in the family Malvaceae, in the subfamilies: Byttnerioideae, Dombeyoideae, Helicteroideae and Sterculioideae.
As traditionally circumscribed the Sterculiaceae, Malvaceae, Bombacaceae, and Tiliaceae comprise the "core Malvales" of the Cronquist system and the close relationship among these families is generally recognized. Sterculiaceae may be separated from Malvaceae sensu stricto by the smooth surface of the pollen grains and the bilocular anthers.
Numerous phylogenetic studies have revealed that Sterculiaceae, Tiliaceae and Bombacaceae as traditionally defined are cladistically polyphyletic. The APG and APG II systems unite Bombacaceae, Malvaceae sensu stricto, Sterculiaceae and Tiliaceae into a more widely circumscribed Malvaceae, i.e., Malvaceae sensu lato. In that view the taxa formerly classified in Sterculiaceae are treated in the subfamilies Byttnerioideae, Dombeyoideae, Helicteroideae and Sterculioideae of the Malvaceae sensu lato. The Thorne system takes an intermediate approach in combining the bulk of the traditional Sterculiaceae (but not including Sterculia itself) with elements of the traditional Tiliaceae to form the family Byttneriaceae.
Sterculiaceae had previously been recognized as a family by most systematists; in its traditional sense the family includes about 70 genera, totalling around 1,500 species of tropical trees and shrubs. The most famous products of the family are chocolate and cocoa from Theobroma cacao, followed by kola nuts. Many species yield timber.
A 2006 molecular study indicated the Sterculioideae was most likely to be a monophyletic group, and that it had four major clades within it. However, the relationships between the clades were not resolved.Theobroma
Theobroma is a genus of flowering plants in the mallow family, Malvaceae, that is sometimes classified as a member of Sterculiaceae. It contains roughly 20 species of small understory trees native to the tropical forests of Central and South America. The generic name is derived from the Greek words θεός (theos), meaning "god," and βρῶμα (broma), meaning "food". It translates to "food of the gods."
Theobroma cacao, the best known species of the genus, is used for making chocolate.Tilia
Tilia is a genus of about 30 species of trees, or bushes, native throughout most of the temperate Northern Hemisphere. In the British Isles they are commonly called lime trees, or lime bushes, although they are not closely related to the tree that produces the lime fruit. Other names include linden for the European species, and basswood for North American species. The genus occurs in Europe and eastern North America, but the greatest species diversity is found in Asia. Under the Cronquist classification system, this genus was placed in the family Tiliaceae, but genetic research summarised by the Angiosperm Phylogeny Group has resulted in the incorporation of this genus, and of most of the previous family, into the Malvaceae.
Tilia species are mostly large, deciduous trees, reaching typically 20 to 40 metres (65 to 130 ft) tall, with oblique-cordate leaves 6 to 20 centimetres (2 1⁄4 to 7 3⁄4 in) across. As with elms, the exact number of species is uncertain, as many if not most of the species will hybridise readily, both in the wild and in cultivation. Limes are hermaphroditic, having perfect flowers with both male and female parts, pollinated by insects.Tiliaceae
Tiliaceae () is a botanical name for a family of flowering plants. It is not a part of the APG, APG II and APG III classifications, being sunk in Malvaceae but has an extensive historical record of use.
All through its existence the family has had a very lively history, with various authors taking very different views on what should be part of this family. As a result, it is recommended when this name is encountered to check what the author means.
However, in the northern temperate regions the name is unambiguous as the only representative is Tilia, the lime or linden.