The sweet pea, ''Lathyrus odoratus'', is a

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Lathyrus ''Lathyrus'' is a genus of flowering plants in the legume family Fabaceae, and contains approximately 160 species. Commonly known as peavines or vetchlings, they are native to temperate areas, with a breakdown of 52 species in Europe, 30 specie ...

'' in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

(

legume Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

s),

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

Sicily Sicily (Italian language, Italian and ), officially the Sicilian Region (), is an island in the central Mediterranean Sea, south of the Italian Peninsula in continental Europe and is one of the 20 regions of Italy, regions of Italy. With 4. ...

, southern

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

and the Aegean Islands. It is an annual climbing plant, growing to a height of , where suitable support is available. The

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

with two leaflets and a terminal

tendril In botany, a tendril is a specialized Plant stem, stem, leaf or Petiole (botany), petiole with a thread-like shape used by climbing plants for support and attachment, as well as cellular invasion by parasitic plants such as ''Cuscuta''. There ar ...

, which twines around supporting plants and structures, helping the sweet pea to climb. In the wild plant the

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are purple, broad; they are larger and highly variable in color in the many

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

s. Flowers are usually strongly scented. The annual

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, ''L. odoratus'', may be confused with the everlasting pea, '' L. latifolius'', a perennial.

Horticultural development

Sweet peas, native to Sicily and Sardinia, were first mentioned by the

Franciscan The Franciscans are a group of related organizations in the Catholic Church, founded or inspired by the Italian saint Francis of Assisi. They include three independent Religious institute, religious orders for men (the Order of Friars Minor bei ...

monk and botanist

Francesco Cupani Francesco Cupani ( 21 January 1657, Mirto, Sicily, Mirto – 19 January 1710, Palermo ) was an Italians, Italian naturalist mainly interested in botany. In 1692 he became the first Director of the botanic garden at Misilmeri. Here the plants w ...

in the ''Hortus Catholicus'' (1696). Cupani first studied medicine, before entering the Franciscan order in 1681 at the age of 24, where he continued to cultivate his interest in natural sciences and botany, particularly to the study of the endemic flora of Sicily. In 1692, Cupani became the first Director of the

botanic garden A botanical garden or botanic gardenThe terms ''botanic'' and ''botanical'' and ''garden'' or ''gardens'' are used more-or-less interchangeably, although the word ''botanic'' is generally reserved for the earlier, more traditional gardens. is ...

Misilmeri Misilmeri () is a town and ''comune'' in the Metropolitan City of Palermo, Sicily. It is approximately from Palermo and its name means "the resting place or the messuage of the Emir", and dates from the Muslim emirate of Sicily. The village rose ...

, where he is believed to have cultivated sweet peas. Cupani's scrambling sweet peas had small, short-stalked, bicolored flowers arranged in pairs and were sweetly scented, but went largely unnoticed by gardeners. Cupani is believed to have sent seed to a number of botanists, including the English botanists

Robert Uvedale Dr Robert Uvedale (1642–1722) was an English cleric teacher and horticulturist. He ran a grammar and boarding school north of London, took part in botanical exchanges, and published as a classical scholar. Life Son of Robert Uvedale of Westmins ...

in Enfield, and Jacob Bobart in Oxford, and the Dutch botanist

Jan Commelin Jan Commelin (23 April 1629 – 19 January 1692), also known as Jan Commelijn, Johannes Commelin or Johannes Commelinus, was a botanist, and was the son of historian Isaac Commelin; his brother Casparus was a bookseller and newspaper publisher. J ...

who published a description and illustration of sweet peas growing in Amsterdam. Despite the general lack of early interest amongst gardeners, some nurserymen including the British horticulturist

Robert Furber Robert Furber (1674–1756) was a British horticulturist and author, best known for writing the first seed catalogue produced in England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is lo ...

began to offer sweet peas for sale as early 1730. Still, by the mid 19th century only 5 cultivars or variants were available; Cupani's wild type sweet pea and types with white, black (or very dark purple), red, or mixed pink and white flowers. Over the course of the 19th century however, horticulturists, nurserymen and gardeners alike began to breed new variants, leading to the formation of dwarf, cretin, hoods and picotee cultivars. The Scottish nurseryman Henry Eckford (1823–1905) cross-bred and developed the sweet pea, turning it from a rather insignificant if sweetly scented flower into a floral sensation of the 19th century. His initial success and recognition came while serving as head gardener for the

Earl of Radnor Earl of Radnor, of the County of Radnor, is a title which has been created twice. It was first created in the Peerage of England in 1679 for John Robartes, 2nd Baron Robartes, a notable political figure of the reign of Charles II. The earldo ...

, raising new cultivars of

pelargonium ''Pelargonium'' () is a genus of flowering plants that includes about 280 species of perennial plant, perennials, succulent plant, succulents, and shrubs, common name, commonly called geraniums, pelargoniums, or storksbills. ''Geranium'' is also ...

s and

dahlia ''Dahlia'' ( , ) is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico and Central America. Dahlias are members of the Asteraceae (synonym name: Compositae) family of dicotyledonous plants, its relatives include the sun ...

s. In 1870 he went to work for one Dr. Sankey of Sandywell near Gloucester. A member of 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 ...

, he was awarded a First Class Certificate (the top award) in 1882 for introducing the sweet pea cultivar 'Bronze Prince', marking the start of association with the flower. In 1888 he set up his development and trial fields for sweet peas in

Wem Wem may refer to: * HMS ''Wem'' (1919), a WWI Royal Navy minesweeper * Weem, a village in Perthshire, Scotland * Wem, a small town in Shropshire, England * Wem (musician), hip hop musician WEM may stand for: * County Westmeath County Westmeat ...

Shropshire Shropshire (; abbreviated SalopAlso used officially as the name of the county from 1974–1980. The demonym for inhabitants of the county "Salopian" derives from this name.) is a Ceremonial counties of England, ceremonial county in the West M ...

. By 1901, he had introduced a total of 115 of the 264

cultivars A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue cult ...

grown at the time. Eckford was presented with the RHS Victoria Medal of Honour for his work. He died in 1906, but his work was continued for a time by his son John Eckford. More recently, the association between the sweet pea, the Eckfords and Wem has been highlighted again. In the late 1980s, the Sweet Pea Society of Wem started an annual show. Many of the street signs now carry a sweet-pea motif, and an area of the town is known as Eckford Park. There is also a cultivar 'Dorothy Eckford', named after a family member.

Cultivation

Sweet peas have been cultivated since the 17th century and a vast number of

are commercially available. They are grown for their flower colour (usually in pastel shades of blue, pink, purple and white, including bi-colours), and for their intense unique fragrance. They are grown by gardeners for private enjoyment or for exhibition, and in the

floristry Floristry is the production, commerce, and trade in flowers. It encompasses flower care and handling, floral design, floral design and arrangement, merchandising, production, display and flower delivery. Wholesale florists sell bulk flowers ...

trade. The large, pea-shaped seeds are sown in

cold frame In agriculture and gardening, a cold frame is a transparent-roofed enclosure, built low to the ground, used to protect plants from adverse weather, primarily excessive cold or wet. The transparent top admits sunlight and prevents heat escape via ...

s in Spring or Autumn. The seeds benefit from pre-soaking or chipping with a sharp blade. The plants are also available later in the season, as young plants or plugs. They are grown up canes, with the new shoots being regularly pinched out to promote a bushy habit and higher flower yields. Plants typically reach heights of , with the flowers appearing in midsummer and continuing for many weeks if regularly deadheaded. Over 50 cultivars have gained the

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

In the UK the National Collection of Sweet Peas was started by Roger Parsons in 1991, when he offered to host a collection of Lathyrus at Hotham Park,

Bognor Regis Bognor Regis (), also known as Bognor, is a town and seaside resort in West Sussex on the south coast of England, south-west of London, west of Brighton, south-east of Chichester and east of Portsmouth. Other nearby towns include Littleham ...

. At the time Parsons was working as Head of Parks and Landscape for Arun District Council. The collection achieved National Collection status in 1993 and now holds about 1300 species and cultivars from around the world. English Sweet Peas, operated by Phil Johnson, now incorporates Roger Parsons Sweet Peas and Johnson will maintain and add to the National Collection. Johnson has submitted an application to Plant Heritage to become the new custodian.

Pests and diseases

The sweet pea plant suffers from some pests, the most common being

aphids Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...

. These insects suck the sap out of the plants, reducing growth.

Mosaic virus A mosaic virus is any virus that causes infected plant foliage to have a mottled appearance. Such viruses come from a variety of unrelated lineages and consequently there is no taxon that unites all mosaic viruses. Examples Virus species tha ...

is spread by greenfly, causing yellowing of leaves, distortion of new shoots, and inhibited flowering. A pest called the

pollen beetle Pollen beetle is an informal term for any species of beetle associated intimately with suitably pollen-rich species of flowers. Typically such a beetle is adapted to the pollen as a major part of its diet. Species in at least sixteen families of th ...

, which is small, shiny and black, eats the pollen and disfigures the flowers. Other pests include caterpillars,

thrips Thrips (Order (biology) , order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Entomologists have species description , described approximately 7,700 species. They fly on ...

slug Slug, or land slug, is a common name for any apparently shell-less Terrestrial mollusc, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced ...

s and

snail A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

s. Another problem is

powdery mildew Powdery mildew is a fungus, fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of Ascomycota, ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant disea ...

; this is a white powdery coating that covers the leaves and slows down growth, and can be caused when sweet peas are planted too close to each other, sucking nutrients from the plants and stunting their growth. The sweet pea is also susceptible to

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon–carbon bond, carbon–carbon doub ...

in quantities produced by senescing plants. Because of this, growers are encouraged to plant sweet peas away from fruit trees among other plants prone to early dieback or senescence.

Toxicity

Unlike the edible

pea Pea (''pisum'' in Latin) is a pulse or fodder crop, but the word often refers to the seed or sometimes the pod of this flowering plant species. Peas are eaten as a vegetable. Carl Linnaeus gave the species the scientific name ''Pisum sativum' ...

, there is evidence that

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s of members of the genus ''Lathyrus'' are toxic if ingested in quantity. A related species, ''

Lathyrus sativus ''Lathyrus sativus'', also known as grass pea, cicerchia, blue sweet pea, chickling pea, chickling vetch, Indian pea, white pea and white vetch, is a legume (family Fabaceae) commonly grown for human consumption and livestock feed in Asia and Eas ...

'', is grown for human consumption but when it forms a major part of the diet it causes symptoms of toxicity called

lathyrism Lathyrism is a condition caused by eating certain legumes of the genus ''Lathyrus''. There are three types of lathyrism: ''neurolathyrism'', ''osteolathyrism'', and ''angiolathyrism'', all of which are incurable, differing in their symptoms and ...

. In studies of rats, animals fed a diet of 50% sweet pea seeds developed enlarged adrenals relative to control animals fed on edible peas. The main effect is thought to be on the formation of collagen. Symptoms are similar to those of

scurvy Scurvy is a deficiency disease (state of malnutrition) resulting from a lack of vitamin C (ascorbic acid). Early symptoms of deficiency include weakness, fatigue, and sore arms and legs. Without treatment, anemia, decreased red blood cells, gum d ...

and copper deficiency, which share the common feature of inhibiting proper formation of collagen fibrils. Seeds of the sweet pea contain beta-aminopropionitrile that prevents the cross-linking of

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

by inhibiting lysyl oxidase and thus the formation of allysine, leading to loose skin. Recent experiments have attempted to develop this chemical as a treatment to avoid disfiguring skin contractions after skin grafting.

Genetics

Gregor Mendel Gregor Johann Mendel Order of Saint Augustine, OSA (; ; ; 20 July 1822 – 6 January 1884) was an Austrian Empire, Austrian biologist, meteorologist, mathematician, Augustinians, Augustinian friar and abbot of St Thomas's Abbey, Brno, St. Thom ...

, who was a Catholic friar, and botanist, is today recognized as the "Father of Modern Genetics" for his work with the cross breeding of

plants (''

Pisum sativum Pea (''pisum'' in Latin) is a pulse or fodder crop, but the word often refers to the seed or sometimes the pod of this flowering plant species. Peas are eaten as a vegetable. Carl Linnaeus gave the species the scientific name ''Pisum sativum ...

'') with different characteristics, and the sweet pea has been used in a similar way. The sweet pea is thus a

model organism A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Mo ...

being used in early experimentations in genetics, particularly by the pioneer geneticist

Reginald Punnett Reginald Crundall Punnett FRS (; 20 June 1875 – 3 January 1967) was a British geneticist who co-founded, with William Bateson, the ''Journal of Genetics'' in 1910. Punnett is probably best remembered today as the creator of the Punnett ...

. It is highly suitable as a genetic subject because of its ability to self-pollinate and its easily observed Mendelian traits such as colour, height and petal form. Many genetic principles were discovered or confirmed in this species. It was used by Punnett in early studies of

genetic linkage Genetic linkage is the tendency of Nucleic acid sequence, DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction. Two Genetic marker, genetic markers that are physically near ...

. Complementary factor inheritance was also elucidated in sweet peas, from the cross of two pure-breeding white strains which gave rise to a blue hybrid, the blue colour requiring two genes derived independently from the two white parents.

Hybridization with ''Lathyrus belinensis''

Like the

blue rose A blue rose is a flower of the genus ''Rosa'' (family Rosaceae) that presents blue-to-violet pigmentation instead of the more common red, white, or yellow, through use of artificial means such as dyes. Blue roses are often used to symbolize myst ...

, the yellow sweet pea remains elusive. '' Lathyrus belinensis'' is a related Lathyrus species which has red and yellow flowers. There are ongoing attempts to bring the yellow colour into ''Lathyrus odoratus'' by hybridizing it with ''Lathyrus belinensis''. Several new hybrid sweet pea cultivars have been created as a result, though not any with the yellow flower colour so far.Dawn Edwards
''Developing a yellow sweet pea''
/ref> The hybrid cultivars belong to the hybrid species '' Lathyrus × hammettii.''

Gallery

File:Sweet Pea-1.jpg File:Sweet Pea-3.jpg File:Sweet Pea-6.jpg File:Sweet Pea-5.jpg File:Sweet Pea-2.jpg File:Sweet Pea-4.jpg File:Edelwicke (Lathyrus odoratus) Blüte focus stack-20200628-RM-175552.jpg, Close up of flower

References

{{Authority control Lathyrus Annual plants Vines Garden plants Garden plants of Europe Plants described in 1753 Nitrogen-fixing crops