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Medicago sativa L.

Overview
General Information
ID Info
Similar Species
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Family :

Famille :

Fabaceae

Synonym(s) :

Synonyme(s) :

Common Name(s) :

Nom(s) commun(s) :

Alfalfa

(English Canada) (USDA-ARS 2024)

Lucerne (English) (Darbyshire 2003)

Lentine (French) (Darbyshire 2003)

Luzerne (French Canada) (USDA-ARS 2024)

Medicago sativa (alfalfa) seeds

  • Medicago sativa (alfalfa) seeds

  • Medicago sativa (alfalfa) seeds

  • Medicago sativa (alfalfa) seed

  • Medicago sativa (alfalfa) seed

  • Medicago sativa (alfalfa) seed

  • Medicago sativa (alfalfa) seed

  • Medicago sativa legumes

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Overview

Aperçu

Regulation :

Remarques Réglementation:

    Regulation Notes:

    Distribution :

    Répartition :

    Medicago sativa (alfalfa) is native to Northern Africa, most of Asia and Europe. It is cultivated and naturalized world-wide (USDA-ARS 2024).

    Habitat and Crop Association :

    Habitat et Cultures Associées :

    Alfalfa is planted as a pasture forage, and hay crop. It is also planted for erosion control. Alfalfa can also be found growing in old fields, roadsides, ditches, and disturbed areas (Darbyshire 2003).

    Alfalfa may be considered both a weed and a crop. Once grown as a crop, it can survive over winter and has the potential to persist in subsequent crops as a volunteer weed. It may be controlled via chemical methods prior to seeding, or after the crop becomes established. Alfalfa can be managed effectively, and in Canada it is not a noxious weed and has not been reported as invasive to natural ecosystems (CFIA 2025).

    Economic Use, cultivation area, and Weed Association :

    Utilisation économique, zone de culture et association de mauvaises herbes :

    Alfalfa has been established as the oldest plant grown solely for forage. It is valued as an animal feed because of its digestibility and high protein content. It is grown by farmers to feed to their livestock as hay or haylage. It can also be dehydrated and processed into meal or pellets. In Canada is grown in combination with perennial forage grasses. This practice reduces alfalfa induced bloat in livestock and extends the usefulness of the crop (CFIA 2025).

     

    Growing alfalfa as part of an agricultural rotation plan offers many benefits. The large taproots aid in aeration, increase the organic matter content, and add structure to the soil. Alfalfa enhances the nitrogen content of the soil for subsequent crops when established plants are plowed into the soil. Crop rotation of alfalfa with other crop kinds (especially cereals and corn) may allow a break in the cycle of pest infestations (CFIA 2025).

     

    Alfalfa is an important source of pollen for honeybees (CFIA 2025).

    Duration of Life Cycle :

    Durée du cycle vital:

    Perennial

    Dispersal Unit Type :

    Type d’unité de dispersion :

    Seed

    General Information

    RENSEIGNEMENTS GÉNÉRAUX

    Within the species Medicago sativa there exist two subspecies which are commonly referred to as alfalfa: M. sativa L. subsp. sativa and M. sativa L. subsp. falcata (L.) Arcang. (USDA-ARS 2024). Crosses of these two subspecies have arisen through natural hybridization, and as a result of agricultural plant breeding. They a have been assigned the name Medicago sativa L. nothosubsp. varia (Martyn) Arcang.
    Between these subspecies there exists a continuum of variation (Small and Brookes 1984). Collectively, these species along with some other less common variants make up a group called the Medicago sativa complex (Quiros and Bauchan).

    M. sativa subsp. sativa is more important agriculturally than the other subspecies and is the most commonly cultivated Medicago sativa subspecies worldwide (Small and Brookes 1984). M. sativa subsp. falcata is cultivated on a limited basis and is cultivated mainly in rangeland conditions in colder climates (CFIA 2025).

    This factsheet will not attempt to distinguish or describe differences in the seed morphology between M. sativa subsp. sativa, M. sativa subsp. falcata or any crosses of these two subspecies. Features described in this factsheet are those displayed by M. sativa in general.

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    Identification

    Identification

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    • Legume: coiled shape

      Size

      Size from literature:

      • Legume (coiled shaped) length: 4 – 14 mm; width: 3 – 9 mm (FNA 1993+)

      Shape

      • Legume (coiled shaped) is spiral shaped with 3 or more coils

      Surface Texture

      • Legume (coiled shaped) has a ridged surface, covered in fine white hairs which may be partially or completely rubbed off

      Colour

      • Legume (coiled shaped) is normally green when fresh, turning brown when mature

      Other Features

      • Medicago sativa subsp. sativa produces legumes of this shape

      Medicago sativa legumes

    • Legume: sickle shaped

      Size

      Size from literature:

      • Legume (sickle shaped) length: 7 – 15 mm; width: 1.5 – 3 mm (FNA 1993+)

      Shape

      • Legume (sickle shaped) is oblong and linear to sickle shaped

      Surface Texture

      • Legume (sickle shaped) has a ridged surface, covered in fine white hairs which may be partially or completely rubbed off

      Colour

      • Legume (sickle shaped) is normally green when fresh, turning brown when mature

      Other Features

      • Medicago sativa subsp. falcata produces legumes of this shape
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    • Seed

      Size

      • Seed length*: 2.1 – 3.03 mm; width: 1.42 – 1.83 mm
      Note: minimum and maximum based on a random selection of 11 seeds in normal range of this species using image measurement protocol (ISMA 2020).

      Seed size from literature:

      • Seed length: 2.2 mm – 2.8 mm; width: 1.2 – 1.5 mm (Bojňanský and Fargašová 2007)
      • Seed length: 1 – 2.5 mm; width: 1 – 1.5 mm (FNA 1993+)

      Shape

      • Seed is kidney-shaped in general, with angular edges. High degree of variability in shape from one seed to the next
      • The shape of the seed is irregular because they develop within a multi-seeded legume
      • Seeds are twisted or bent
      • Radicle may or may not be divergent from the cotyledons

      Surface Texture

      • Seed surface texture is smooth

      Colour

      • Seeds are yellow, green, yellowish green and turn brown or orangish brown as they age
      • The area where the radicle furrow is located is lighter colour than the rest of the seed
      • The seed coat surrounding the hilum is a reddish-brown colour
      • The seed coat may be brown in the area where the lens is located

      Other Features

      • The radicle furrow can be described as a slight indentation on the surface of the seed located between the radicle and the cotyledons. It is an area of space between these seed structures and looks like a very narrow triangle which tapers rapidly from the hilum into a narrow line near the centre of the seed. The radicle furrow is not parallel to radicle edge.
      • Radicle lobe is ½ to nearly ⅔ the length of the cotyledon lobe
      • Hilum located near the middle of the long axis, close to the radicle tip. It is round and sometimes has some off-white flakey tissue attached to it.

      Medicago sativa (alfalfa) seeds

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    • Embryo

      Size

      • Embryo size is filled

      Shape

      • Embryo is bent: the hypocotyl bends so that the radicle lies folded on top of the cotyledons.

      Endosperm

      • Cotyledons are large, thick (ISTA 2021), and provide nutrition to the developing embryo

      Other Features

      • Embryo is in the axial position

    Identification Tips

    CONSEILS POUR L’IDENTIFICATION

    Medicago sativa seeds can be quite variable in size and shape, but when rested on its narrow side (edge) with hilum facing up, the seed appears twisted and is not symmetrical. Furthermore, an alfalfa seed cannot be balanced on its narrowest plane compared to white and yellow sweet clover seeds.

    Medicago sativa (alfalfa) seed

    Additional Botany Information

    AUTRES RENSEIGNEMENTS BOTANIQUES

    Flowers/Inflorescence

    • Medicago sativa subsp. sativa has purple flowers and coiled legumes (CFIA 2025)
    • Medicago sativa subsp. sativa flowers may also be violet in colour and are rarely white (FNA 1993+)
    • Medicago sativa subsp. falcata has yellow flowers and straight to sickle shaped pods (CFIA 2025)
    • Medicago sativa × varia has variegated yellow and violet flowers, but may sometimes be green, yellow, or violet (FNA 1993+)

    Vegetative Features

    • Medicago sativa plants may be upright or prostrate (FRNA 1993+)
    • Medicago sativa leaflets have blades that may be egg-shaped or linear and are 5 to 35 mm long and 2 – 15 mm wide (FNA 1993+)

    Similar Species

    ESPÈCES SEMBLABLES

    Similar species are based on a study of seed morphology of various species, and those with similar dispersal units are identified. The study is limited by physical specimen and literature availability at the time of examination, and possibly impacted by the subjectivity of the authors based on their knowledge and experience. Providing similar species information for seed identification is to make users aware of similarities that could possibly result in misidentification.

    Medicago lupulina L. (black medick)
    Black medick seed is rounded and symmetrical, and has a straight axis and a uniform shape, unlike alfalfa seed which is relatively flat and bent with an angular outline. The radicle of black medick protrudes as a small, rounded bump. The cotyledon lobes are broadly rounded. The radicle line is wide near the hilum becoming very narrow as it extends and curves slightly towards the cotyledons. The legume is a dark brown, or black colour and often remains attached to the seed.

    Melilotus albus Medik. (white sweet clover) and Melilotus officinalis (L.) Lam. (yellow sweet clover)
    Sweet clover seeds are a slightly different shape than those of alfalfa, they are symmetrical, oval and are not twisted or bent. They have a dull surface compared to alfalfa which is lustrous. Sweet clover can be balanced on its narrowest plane, while alfalfa cannot balance this way.

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    Reference(s)

    Référence(s)

    Canadian Food Inspection Agency (CFIA). 2025. The Biology of Medicago sativa L. (Alfalfa) – inspection.canada.ca Accessed January 08, 2025.

    Bojnanský, V., & Fargašová, A. 2007. Atlas of Seeds and Fruits of Central and East-European Flora. Dordrecht, The Netherlands: Springer.

    Darbyshire, S. J. 2003. Inventory of Canadian Agricultural Weeds. Agriculture and Agri-Food Canada, Research Branch. Ottawa, ON.

    Flora of North America (FNA) Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 22+ vols. New York and Oxford. http://beta.floranorthamerica.org Accessed April 11, 2025.

    International Seed Morphology Association (ISMA). 2020. Method for Seed Size Measurement. Version 1.0. ISMA Publication Guide. https://www.idseed.org/authors/details/method_for_seed_size_measurement.html

    International Seed Testing Association (ISTA). 2021. Universal List of Species. https://www.seedtest.org/en/services-header/tools/purity-committee/universal-list-species.html

    Quiros, C.F. and Bauchan, G.R. 1988. The genus Medicago and the origin of the Medicago sativa complex. in: Hanson, A.A., Barnes, D.K. and Hill Jr. R.R. (Eds.), Alfalfa and Alfalfa Improvement, Volume 29. pp. 93-124. ASA-CSSA-SSSA, Madison, WI.

    United States Department of Agriculture-Agricultural Research Services (USDA-ARS). 2024. Germplasm Resources Information Network (GRIN). http://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=16637 Accessed December 18, 2024.

    Small, E., & Brookes, B. (1984). Taxonomic circumscription and identification in the Medicago sativa-falcata (Alfalfa) continuum. Economic Botany, 38, 83–96. Retrieved from http://www.jstor.org/stable/4254576

    Author(s)

    AUTEUR(S)

    Janessa Emerson, Julie Lu, Angela Salzl
    Canadian Food Inspection Agency, Canada ssts@inspection.gc.ca

    contactus@idseed.org

    Last updated
    on 2023-03-27

    © 2025 ISMA - International Seed Morphology Association