Medicago

Medicago is a genus of flowering plants, commonly known as medick or burclover, in the legume family (Fabaceae). It contains at least 87 species and is distributed mainly around the Mediterranean Basin, and extending across temperate Eurasia and sub-Saharan Africa. The best-known member of the genus is alfalfa (M. sativa), an important forage crop, and the genus name is based on the Latin name for that plant from Median (grass). Most members of the genus are low, creeping herbs, resembling clover, but with burs (hence the common name). However, alfalfa grows to a height of 1 meter, and tree medick (M. arborea) is a shrub. Members of the genus are known to produce bioactive compounds such as medicarpin (a flavonoid) and medicagenic acid (a triterpenoid saponin). Chromosome numbers in Medicago range from 2n = 14 to 48.
The species Medicago truncatula is a model legume due to its relatively small stature, small genome (450–500 Mbp), short generation time (about 3 months), and ability to reproduce both by outcrossing and selfing.
Comprehensive descriptions of the genus are Lesinš and Lesinš 1979 and Small and Jomphe 1989. Major collections are SARDI (Australia), USDA-GRIN (United States), ICARDA (Syria), and INRA (France).
Evolution
Medicago diverged from Glycine (soybean) about 53–55 million years ago (in the early Eocene), from Lotus (deervetch) 49–51 million years ago (also in the Eocene), and from Trigonella 10–22 million years ago (in the Miocene).
Ecological interactions with other organisms
Symbiosis with nitrogen-fixing rhizobia
Béna et al. (2005) constructed a molecular phylogeny of 23 Sinorhizobium strains and tested the symbiotic ability of six strains with 35 Medicago species. Comparison of these phylogenies indicates many transitions in the compatibility of the association over evolutionary time. Furthermore, they propose that the geographical distribution of strains limits the distribution of particular Medicago species.
Agricultural uses
Other than alfalfa, several of the creeping members of the family (such as Medicago lupulina and Medicago truncatula) have been used as forage crops.
Insect herbivores
Medicago species are used as food plants by the larvae of some Lepidoptera species including the common swift, flame, latticed heath, lime-speck pug, nutmeg, setaceous Hebrew character, and turnip moths and case-bearers of the genus Coleophora, including C. frischella (recorded on M. sativa) and C. fuscociliella (feeds exclusively on Medicago spp.).
Species
This list is compiled from:
Section Buceras
Subsection Deflexae
Medicago retrorsa (Boiss.) E. Small
Subsection Erectae
Medicago arenicola (Huber-Mor.) E. Small
Medicago astroites (Fisch. & Mey.) Trautv.
Medicago carica (Huber-Mor.) E. Small
Medicago crassipes (Boiss.) E. Small
Medicago fischeriana (Ser.) Trautv.
Medicago halophila (Boiss.) E. Small
Medicago heldreichii (Boiss.) E. Small
Medicago medicaginoides (Retz.) E. Small
Medicago monantha (C. A. Meyer) Trautv.
Medicago orthoceras (Kar. & Kir.) Trautv.
Medicago pamphylica (Huber-Mor. & Sirjaev) E. Small
Medicago persica (Boiss.) E. Small
Medicago phrygia (Boiss. & Bal.) E. Small
Medicago polyceratia (L.) Trautv.
Medicago rigida (Boiss. & Bal.) E. Small
Subsection Isthmocarpae
Medicago rhytidiocarpa (Boiss. & Bal.) E. Small
Medicago isthmocarpa (Boiss. & Bal.) E. Small
Subsection Reflexae
Medicago monspeliaca (L.) Trautv.
Section Carstiensae
Medicago carstiensis Wulf.
Section Dendrotelis
Medicago arborea L.
Medicago citrina (Font Quer) Greuter
Medicago strasseri Greuter, Matthas & Risse
Section Geocarpa
Medicago hypogaea E. Small
Section Heynianae
Medicago heyniana Greuter
Section Hymenocarpos
Medicago radiata L.
Section Lunatae
Medicago biflora (Griseb.) E. Small
Medicago brachycarpa M. Bieb.
Medicago huberi E. Small
Medicago rostrata (Boiss. & Bal.) E. Small
Section Lupularia
Medicago lupulina L.
Medicago secundiflora Durieu
Section Medicago
Medicago cancellata M. Bieb.
Medicago daghestanica Rupr.
Medicago hybrida (Pourr.) Trautv.
Medicago marina L.
Medicago papillosa Boiss.
M. p. macrocarpa
M. p. papillosa
Medicago pironae Vis.
Medicago prostrata Jacq.
M. p. prostrata
M. p. pseudorupestris
Medicago rhodopea Velen.
Medicago rupestris M. Bieb
Medicago sativa L. (alfalfa)
M. s. caerulea
M. s. falcata (Medicago falcata)
M. s. f. var. falcata
M. s. f. var. viscosa
M. s. glomerata
M. s. sativa
* Medicago saxatilis M. Bieb
Medicago suffruticosa Ramond ex DC.
M. s. leiocarpa
M. s. suffruticosa
Section Orbiculares
Medicago orbicularis (L.) Bart.
Section Platycarpae
Medicago archiducis-nicolai Sirjaev
Medicago cretacea M. Bieb.
Medicago edgeworthii Sirjaev
Medicago ovalis (Boiss.) Sirjaev
Medicago playtcarpa (L.) Trautv.
Medicago plicata (Boiss.) Sirjaev
Medicago popovii (E. Kor.) Sirjaev
Medicago ruthenica (L.) Ledebour
Subsection Rotatae
Medicago blancheana Boiss.
Medicago noeana Boiss.
Medicago rugosa Desr.
Medicago rotata Boiss.
Medicago scutellata (L.) Miller
Medicago shepardii Post
Section Spirocarpos
Subsection Intertextae
Medicago ciliaris (L.) Krocker
Medicago granadensis Willd.
Medicago intertexta (L.) Miller
Medicago muricoleptis Tin.
Subsection Leptospireae
Medicago arabica (L.) Huds.
Medicago coronata (L.) Bart.
Medicago disciformis DC.
Medicago laciniata (L.) Miller
Medicago lanigera Winkl. & Fedtsch.
Medicago laxispira Heyn
Medicago minima (L.) Bart.
Medicago polymorpha L.
Medicago praecox DC.
Medicago sauvagei Nègre
Medicago tenoreana Ser.
Subsection Pachyspireae
Medicago constricta Durieu
Medicago doliata Carmign.
Medicago italica (Miller) Fiori
Medicago lesinsii E. Small
Medicago littoralis Rohde ex Lois.
Medicago murex Willd.
Medicago rigidula (L.) All.
Medicago rigiduloides E. Small
Medicago sinskiae Uljanova
Medicago soleirolii Duby
Medicago sphaerocarpos Bertol.
Medicago syriaca E. Small
Medicago truncatula Gaertn.
Medicago turbinata (L.) All.
Species names with uncertain taxonomic status
The status of the following species is unresolved:
Medicago agropyretorum Vassilcz.
Medicago alatavica Vassilcz.
Medicago caucasica Vassilcz.
Medicago cyrenaea Maire & Weiller
Medicago difalcata Sinskaya
Medicago grossheimii Vassilcz.
Medicago gunibica Vassilcz.
Medicago hemicoerulea Sinskaya
Medicago karatschaica (A. Heller) A. Heller
Medicago komarovii Vassilcz.
Medicago meyeri Gruner
Medicago polychroa Grossh.
Medicago schischkinii Sumnev.
Medicago talyschensis Latsch.
Medicago transoxana Vassilcz.
Medicago tunetana (Murb.) A.W. Hill
Medicago vardanis' Vassilcz.
Medicago virescens Grossh.
Recent molecular phylogenic analyses of Medicago'' indicate that the sections and subsections defined by Small & Jomphe, as outlined above, are generally polyphyletic. However, with minor revisions sections and subsections could be rendered monophyletic.
Notes
References
Plant models
Fabaceae genera
Taxa named by Carl Linnaeus