Lupinus

Lupinus, commonly known as lupin, lupine,^{[note 1]} or regionally bluebonnet, is a genus of plants in the legume family Fabaceae. The genus includes over 199 species, with centres of diversity in North and South America.^[1] Smaller centres occur in North Africa and the Mediterranean.^[1][2] They are widely cultivated both as a food source and as ornamental plants, but are invasive to some areas. For instance, lupine has become an ecological problem in Iceland since the beginning of the 21st century.^[3]

The part of the plant which is eaten is the leguminous seed. It is nutritious, sustainable, and affordable.^[4] Because they are bitter and contain strong alkaloids, they must be pickled prior to consumption, to avoid toxicity.^[5]

The species are mostly herbaceousperennial plants0.3–1.5 metres (1–5 feet) tall, but some are annual plants and a few are shrubs up to 3 m (10 ft) tall. An exception is the chamis de monte (Lupinus jaimehintonianus) of Oaxaca in Mexico, which is a tree up to 8 m (26 ft) tall.^[6]

Lupins have soft green to grey-green leaves which may be coated in silvery hairs, often densely so. The leaf blades are usually palmately divided into five to 28 leaflets, or reduced to a single leaflet in a few species of the southeastern United States and eastern South America.^[7]

The flowers are produced in dense or open whorls on an erect spike, each flower 1–2 centimetres (3⁄8–3⁄4 inch) long. The pea-like flowers have an upper standard, or banner, two lateral wings, and two lower petals fused into a keel. The flower shape has inspired common names such as bluebonnets and quaker bonnets.

The fruit is a pod containing several seeds. The seeds contain alkaloids which lend them a bitter taste.

Extrafloral nectaries have been found on a species in Arizona.^[8]

The genus Lupinus L. and, in particular, its North American species were divided by Sereno Watson (1873) into three sections: Lupinus, Platycarpos, and Lupinnelus. Differences in habitat and in the number of ovules were the basis for this classification. A majority of the perennial and annual species from the American continent described by Watson were referred to Lupinus. Some annual species with two ovules in the ovary and two seeds in the pod (L. densiflorus, L. microcarpus, etc.) were attributed to the Platycarpos section. Section Lupinnelus consisted of one species (L. uncialis), with axillary and solitary flowers, scarcely reflexed banner, and also with two ovules in the ovary.

While Watson's work was predominantly based on study of North American species, the later research of Ascherson and Graebner (1907) extended his principle of classification to cover all lupins from the Eastern and Western Hemispheres, also using number of ovules (seedbuds) in the ovary (and thus of seeds in the pod) as the criterion for this division. They described two subgenera, Eulupinus and Platycarpos. Most of the described species were referred to subgen. A. Eulupinus. Subgen. B. Platycarpos included several annual species from the Eastern Hemisphere with two seedbuds and seeds in the bean (the same species, as the one specified by S. Watson).

A current schema retains this distinction, but uses the nomenclature for the subgenera of Platycarpos and Lupinus. In this schema, subgenus Platycarpos (S.Wats.) Kurl. contains perennial and annual species from the Western Hemisphere, with a minimum two or more ovules or seedbuds. Subgenus Lupinus consists of 12 species from Africa and the Mediterranean, with a minimum of four ovules or seedbuds.^[9]

The taxonomy of Lupinus has always been confusing. How many distinct species exist or how they might be organized within the genus is not clear. The plants are variable and the taxa are not always distinct from one another. Some American taxa have been described as complexes rather than separate species.^[10] Estimates of the number of lupine species generally fall between 200 and 500.^[2] One authority places the estimate at approximately 267 species worldwide.^[1] Currently, two subgenera are recognized.

Certain species, such as the yellow bush lupin (L. arboreus), are considered invasive weeds when they appear outside their native ranges. In New Zealand, lupines are viewed as invasive and a severe threat in some cases.^[48]L. polyphyllus has escaped into the wild and grows in large numbers along main roads and streams on the South Island. A similar spread of the species has occurred in Sweden, Finland and Norway after the non-native species was first deliberately planted in the landscaping along the main roads. Lupins have been planted in some parts of Australia with a considerably cooler climate, particularly in rural Victoria and New South Wales.

Lupins are important larval food plants for many lepidopterans (butterflies and moths). These include:

• Iraricia icarioides missionensis (Mission blue butterfly), larvae limited to Lupinus^[49]
• Callophrys irus (frosted elfin), recorded on L. perennis^[50]
• Erynnis persius (Persius duskywing)^[51]
• †Glaucopsyche xerces (Xerces blue)
• Glaucopsyche lygdamus (silvery blue)^[52]
• Plebejus melissa samuelis (Karner blue)^[53]
• Erynnis persius persius (eastern Persius duskywing)^[54]
• Schinia sueta, larvae limited to Lupinus^[55]

Lupinus polyphyllus, the garden lupin, and Lupinus arboreus, the tree lupin, are popular ornamental plants in gardens, and are the source of numerous hybrids and cultivars in a wide range of colours, including bicolors. As legumes, lupins are good companion plants in gardens, increasing the soil nitrogen for vegetables and other plants. As well as growing in the ground, lupins can do well in pots on balconies or patios.^[56]

• 
  Russell hybrid lupin Lupinus polyphyllus, UK
• 
  Lupinus sp., Raspberry Island, Alaska, United States
• 
  Lupins in Hokkaido, Japan
• 
  Lupin cultivar "My Castle"
• 
  Ornamental lupins, Ushuaia, Argentina
• 
  Lupins at Lake Tekapo, New Zealand
• 
  Lupins at Lake Tekapo, New Zealand
• 
  Texas Bluebonnet, Texas, United States
• 
  Lupins in Pacific NorthwestWashington, United States

Some lupins contain certain secondary compounds, including isoflavones and toxic alkaloids,^[57] such as lupinine, anagyrine and sparteine. With early detection, these can be removed through processing, although lupins containing these elements are not usually selected for food-grade products.

A risk of lupin allergy exists in patients allergic to peanuts.^[61] Most lupin reactions reported have been in people with peanut allergy.^[62] Because of the cross-allergenicity of peanut and lupin, the European Commission, as of 2006, has required that food labels indicate the presence of "lupin and products thereof" in food.^[63]

Lupin plants can be colonized by the fungus Diaporthe toxica^[64] which can cause a mycotoxicosis known as lupinosis when ingested by grazing animals.

The legume seeds of lupins, commonly called lupin beans, were popular with the Romans, who cultivated the plants throughout the Roman Empire where the lupin is still known in extant Romance languages by names such as lupini.

Seeds of various species of lupins have been used as a food for over 3,000 years around the Mediterranean^[65] and for as long as 6,000 years in the Andes.^[66] Lupins were also used by many Native American peoples of North America such as the Yavapai. The Andean lupin or tarwi (Lupinus mutabilis) was a widespread food in the Incan Empire; but they have never been accorded the same status as soybeans, dry peas and other pulse crops. The pearl lupin of the Andean highlands of South America, L. mutabilis, known locally as tarwi or chocho, was extensively cultivated, but no conscious genetic improvement other than to select for larger and water-permeable seeds seems to have been made. Users soaked the seed in running water to remove most of the bitter alkaloids and then cooked or toasted the seeds to make them edible,^[67] or else boiled and dried them to make kirku,^[66] reported as a pre-Columbian practice in Las Relaciones geográficas de Indias.^[68] Spanish domination led to a change in the eating habits of the indigenous peoples, and only recently^[69] (late 20th century onward) has interest in using lupins as a food been renewed.^[70][65]:353

Lupins can be used to make a variety of foods both sweet and savoury, including everyday meals, traditional fermented foods, baked foods, and sauces. The European white lupin (L. albus) beans are commonly sold in a salty solution in jars (like olives and pickles) and can be eaten with or without the skin. Lupini dishes are most commonly found in Europe, especially in Portugal, Spain, Greece, and Italy. They are also common in Brazil and Egypt. In Egypt, the lupin is known in Arabic as ترمسtermes, and is a popular street snack after being treated with several soakings of water, and then brined. In Portugal, Spain, and the Spanish Harlem district of New York City, they are consumed with beer and wine. In the Levant region, the salty and chilled beans are called turmus (in Arabic: تُرمُس, Hebrew: תורמוס) and are served as part of an apéritif or a snack. Other species, such as L. albus (white lupin), L. angustifolius (narrow-leafed lupin),^[71] and L. hirsutus (blue lupin)^[72] also have edible seeds.^[73]

Consumed throughout the Mediterranean region and the Andean mountains, lupins were eaten by the early Egyptian and pre-Incan people and were known to Roman agriculturalists for their ability to improve the fertility of soils.^[74]

In the late 18th century, lupins were introduced into northern Europe as a means of improving soil quality, and by the 1860s, the garden yellow lupin was seen across the sandy soils of the Baltic coastal plain.

The successful development of lupin varieties with the necessary "sweet gene" paved the way for the greater adoption of lupins across Europe and later Australia.

Further work carried out by the Western Australian Department of Agriculture and Food during the 1950s and '60s has led to more sweet lupin crops being produced in Western Australia now than anywhere else in the world.

Bluebonnets, including the Texas bluebonnet (L. texensis), are the state flowers of Texas.

• Alice Eastwood
• Lupinus mutabilis, an edible species of Lupinus

• Eastwood, R. J., et al. 2008. Diversity and evolutionary history of lupins—insights from new phylogenies. pp. 346–54, In: Palta, J. A. and J. B. Burger. (Eds.) Lupins for Health & Wealth. Proceedings 12th International Lupin Conference, Fremantle, Australia; International Lupin Association, Canterbury, New Zealand.
• Putnam, D. H., et al. Lupine. Alternative Field Crops Manual. University of Minnesota, University of Wisconsin Extension. 1997.
• Zhukovsky, P.M. 1929. A contribution to the knowledge of genus Lupinus Tourn. Bull. Apll. Bot. Gen. Pl.-Breed., Leningrad-Moscow, XXI, I:16-294.
• Kurlovich, B.S. 1989. On the centers of species formation of the genus LupinusL. (in Russian). Bull.N.I. Vavilov Inst. of plant Industry. Leningrad, 193:20–24.
• Kurlovich, B.S., Rep’ev, S.I., Shchelko, L.G., Budanova, V.I., Petrova, M.V., Buravtseva, T.V., Stankevich, A.K., Kartuzova, L.T., Alexandrova, T.G., Teplyakova and T.E., Malysh, L.K. 1995. Theoretical basis of plant breeding. Vol.111. The gene bank and breeding of grain legumes (lupine, vetch, soya, and bean), St.Petersburg, VIR, 438p.
• Kurlovich, B.S.(Ed.). 2002. Lupins. Geography, Classification, Genetic Resources and Breeding. "Intan", 468p.

• Media related to Lupinus at Wikimedia Commons
• Data related to Lupinus at Wikispecies
• Sorting Lupinus Names Multilingual Multiscript Plant Name Database. University of Melbourne.
• Biodiversity of LUPINS
• Hughes, C. Lupinus.Archived 1 April 2011 at the Wayback Machine
• Lupins.org
• Superhydrophobicity in Lupins – video and commentary.