''Malus'' ( or ) is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of about 30–55

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 appropriate s ...

of small

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s or

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 in the family

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are ''Alchemilla'' (270), ''Sorbus ...

, including the domesticated orchard

apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

, crab apples,

wild apple ''Malus sieversii'' is a wild apple native to the mountains of Central Asia in southern Kazakhstan. It has recently been shown to be the primary ancestor of most cultivars of the domesticated apple (''Malus domestica''). It was first described as ...

s, and rainberries. The genus is

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 the

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

zone of the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

Description

Apple trees are typically talI at maturity, with a dense, twiggy crown. 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 long, alternate, simple, with a serrated margin. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are borne in

corymb Corymb is a botanical term for an inflorescence with the flowers growing in such a fashion that the outermost are borne on longer pedicels than the inner, bringing all flowers up to a common level. A corymb has a flattish top with a superficial re ...

s, and have five

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, which may be white, pink, or red, and are perfect, with usually red stamens that produce copious

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

, and a half-inferior ovary; flowering occurs in the spring after 50–80

growing degree day Growing degree days (GDD), also called growing degree units (GDUs), are a heuristic tool in phenology. GDD are a measure of heat accumulation used by horticulturists, gardeners, and farmers to predict plant and animal development rates such as the ...

s (varying greatly according to subspecies and

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, ...

). Many apples require

cross-pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, ...

between individuals by

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

s (typically

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...

s, which freely visit the flowers for both

nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

and

); these are called self-sterile, so self-pollination is impossible, making pollinating insects essential. A number of cultivars are self-pollinating, such as 'Granny Smith' and 'Golden Delicious', but are considerably fewer in number compared to their cross-pollination dependent counterparts. Several ''Malus'' species, including domestic apples,

hybridize Hybridization (or hybridisation) may refer to: *Hybridization (biology), the process of combining different varieties of organisms to create a hybrid *Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals *Nu ...

freely. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

is a globose

pome In botany, a pome is a type of fruit produced by flowering plants in the subtribe Malinae of the family Rosaceae. Well-known pomes include the apple, pear, and quince. Etymology The word ''pome'' entered English in the late 14th century, and re ...

, varying in size from in diameter in most of the wild species, to in ''M. sylvestris sieversii'', in ''M. domestica'', and even larger in certain cultivated orchard apples. The centre of the fruit contains five

carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

s arranged star-like, each containing one or two

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

Subdivisions and species

About 42 to 55 species and natural hybrids are known, with about 25 from China, of which 15 are endemic. The genus ''Malus'' is subdivided into eight sections (six, with two added in 2006 and 2008). The genus ''

Docynia ''Docynia'' (栘𣐿属, ''yí yī shǔ'') is a genus of flowering trees, evergreen or semi-evergreen, in the family Rosaceae. The fruit is a pome. The tree is endemic to Southeast Asia, including Myanmar Myanmar, ; UK pronunciations: ...

'' has been shown to be nested within ''Malus'' in molecular phylogenies. The oldest fossils of the genus date to the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

(

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Midd ...

), which are leaves belonging to the species ''Malus collardii'' and ''Malus kingiensis'' from western North America (Idaho) and the

Russian Far East The Russian Far East (russian: Дальний Восток России, r=Dal'niy Vostok Rossii, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is admini ...

(

Kamchatka The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and wes ...

), respectively.

Natural hybrids

* '' Malus × micromalus'' – midget crabapple

Fossil species

After * ''Malus collardii'' Axelrod, North America (Idaho),

* ''Malus kingiensis'' Budants, Kamchatka Peninsula, Russia, Eocene * ''Malus florissantensis'' (Cockerell) MacGinitie

Green River Formation The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine ...

, North America (Colorado) Eocene * ''Malus pseudocredneria'' (Cockerell) MacGinitie Green River Formation, North America (Colorado) Eocene * ''Malus idahoensis'' R.W.Br. North America (Idaho),

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

* ''Malus parahupehensis'' J.Hsu and R.W.Chaney

Shanwang The Shanwang National Geology Park () is located in central Shandong province, People's Republic of China, about from Linqu County. It has an area of about . The Park is well known for its fossil bearing diatomitic deposits, one of only a few such ...

, Shandong, China, Miocene * ''Malus antiqua'' Doweld Romania,

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

Cultivation

Crabapples are popular as compact ornamental trees, providing blossom in spring and colourful fruit in autumn. The fruits often persist throughout winter. Numerous hybrid cultivars have been selected. Some crabapples are used as

rootstock A rootstock is part of a plant, often an underground part, from which new above-ground growth can be produced. It could also be described as a stem with a well developed root system, to which a bud from another plant is grafted. It can refer to a ...

s for domestic apples to add beneficial characteristics. For example, the rootstocks of ''

Malus baccata ''Malus baccata'' is an Asian species of apple known by the common names Siberian crab apple, Siberian crab, Manchurian crab apple and Chinese crab apple. It is native to much of northern Asia, but is also grown elsewhere as an ornamental tree an ...

'' varieties are used to give additional cold hardiness to the combined plants for orchards in cold northern areas. They are also used as

pollinizer {{Unreferenced, date=May 2009 A pollenizer (or polleniser), sometimes pollinizer (or polliniser, see spelling differences) is a plant that provides pollen. The word '' pollinator'' is often used when ''pollenizer'' is more precise. A pollinato ...

s in apple

orchard An orchard is an intentional plantation of trees or shrubs that is maintained for food production. Orchards comprise fruit- or nut-producing trees which are generally grown for commercial production. Orchards are also sometimes a feature of larg ...

s. Varieties of crabapple are selected to bloom contemporaneously with the apple variety in an orchard planting, and the crabs are planted every sixth or seventh tree, or limbs of a crab tree are grafted onto some of the apple trees. In emergencies, a bucket or drum bouquet of crabapple flowering branches is placed near the beehives as orchard pollenizers. Because of the plentiful blossoms and small fruit, crabapples are popular for use in

bonsai Bonsai ( ja, 盆栽, , tray planting, ) is the Japanese art of growing and training miniature trees in pots, developed from the traditional Chinese art form of ''penjing''. Unlike ''penjing'', which utilizes traditional techniques to produce ...

culture.

Cultivars

These cultivars have won 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 (Nort ...

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 ...

:- *'Adirondack' *'Butterball' * 'Comtesse de Paris' *'Evereste' *'Jelly King'='Mattfru' *'Laura' *''

Malus × robusta ''Malus'' × ''robusta'', called Siberian crab apple along with other members of its genus, is a hybrid species of flowering plant in the family Rosaceae. It is the result of a cross between ''Malus baccata'' (Siberian crab apple) and '' Malus p ...

'' 'Red Sentinel' *'Sun Rival' Other varieties are dealt with under their species names.

Toxicity

The seeds contain

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

compounds.

Uses

Crabapple fruit is not an important

crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydroponic ...

in most areas, being extremely

sour The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...

due to

malic acid Malic acid is an organic compound with the molecular formula . It is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms ...

(which like the genus derives from the Latin name '' mālum''), and in some species woody, so is rarely eaten raw. In some

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

n cultures, they are valued as a sour

condiment A condiment is a preparation that is added to food, typically after cooking, to impart a specific Flavoring, flavor, to enhance the flavor, or to complement the dish. A table condiment or table sauce is more specifically a condiment that is serv ...

, sometimes eaten with salt and

chilli Chili or chilli may refer to: Food * Chili pepper, the spicy fruit of plants in the genus ''Capsicum''; sometimes spelled "chilli" in the UK and "chile" in the southwestern US * Chili powder, the dried, pulverized fruit of one or more varieties ...

shrimp paste Shrimp paste or prawn sauce is a fermented condiment commonly used in Southeast Asian and Southern Chinese cuisines. It is primarily made from finely crushed shrimp or krill mixed with salt, and then fermented for several weeks. They are eithe ...

. Some crabapple varieties are an exception to the reputation of being sour, and can be very sweet, such as the 'Chestnut' cultivar. Crabapples are an excellent source of

pectin Pectin ( grc, πηκτικός ': "congealed" and "curdled") is a heteropolysaccharide, a structural acid contained in the primary lamella, in the middle lamella, and in the cell walls of terrestrial plants. The principal, chemical component of ...

, and their

juice Juice is a drink made from the extraction or Cold-pressed juice, pressing of the natural liquid contained in fruit and vegetables. It can also refer to liquids that are flavored with concentrate or other biological food sources, such as meat ...

can be made into a ruby-coloured

preserve The word preserve may refer to: Common uses * Fruit preserves, a type of sweet spread or condiment * Nature reserve, an area of importance for wildlife, flora, fauna or other special interest, usually protected Arts, entertainment, and media ...

with a full, spicy flavour. A small percentage of crabapples in

cider Cider ( ) is an alcoholic beverage made from the fermented juice of apples. Cider is widely available in the United Kingdom (particularly in the West Country) and the Republic of Ireland. The UK has the world's highest per capita consumption, ...

makes a more interesting flavour. As

Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlement of Britain, Anglo ...

''Wergulu'', the crab apple is one of the nine plants invoked in the pagan Anglo-Saxon ''

Nine Herbs Charm The "Nine Herbs Charm" is an Old English charm recorded in the tenth-century CEGordon (1962:92–93). Anglo-Saxon medical compilation known as ''Lacnunga'', which survives on the manuscript, Harley MS 585, in the British Library, at London.Macleo ...

'', recorded in the 10th century. Applewood gives off a pleasant scent when burned, and smoke from an applewood fire gives an excellent flavour to smoked foods. It is easier to cut when green; dry applewood is exceedingly difficult to carve by hand. It is a good wood for cooking fires because it burns hot and slow, without producing much flame.

Gallery

File:Apple blossom. Eastern Siberia.jpg, Apple blossom. Eastern Siberia File:Crabapples.jpg, Ripe wild crab apples (''Malus sylvestris'') File:Lee-Russell-Farm-Security-Administration-1939-Crab-Apples.jpg, Baskets of crab apples for sale in Connecticut in 1939 File:20071103Tradkrafta1.JPG, Trunk

References

External links

Germplasm Resources Information Network: ''Malus''

Flora of China: ''Malus''

a cooperative among

Purdue University Purdue University is a public land-grant research university in West Lafayette, Indiana, and the flagship campus of the Purdue University system. The university was founded in 1869 after Lafayette businessman John Purdue donated land and money ...

Rutgers University Rutgers University (; RU), officially Rutgers, The State University of New Jersey, is a Public university, public land-grant research university consisting of four campuses in New Jersey. Chartered in 1766, Rutgers was originally called Queen's ...

, and the

University of Illinois The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the University ...

. {{Authority control Rosaceae genera Plants used in bonsai Fruit trees Taxa named by Philip Miller