''Desmodium'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of plants in the legume family Fabaceae, sometimes called tick-trefoil, tick clover, hitch hikers or beggar lice. There are dozens of

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 ...

and the delimitation of the genus has shifted much over time. These are mostly inconspicuous plants; few have bright or large flowers. Though some can become sizeable plants, most are herbs or small shrubs. Their fruit are

loment A loment (or lomentum) is a type of dehiscent legume fruit that breaks apart at constrictions occurring between segments, so that each segment contains one seed. It is a type of schizocarp. Tick trefoil (''Desmodium'') and sweet vetch (''Hedysarum ...

s, meaning each

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 ...

is dispersed individually enclosed in its segment. This makes them tenacious plants and some species are considered

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

s in places. They have a variety of uses.

Uses

Several ''Desmodium'' species contain potent

secondary metabolites Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the nor ...

that are released into the soil and aerially. Allelopathic compounds are used in agriculture in push-pull technology: '' Desmodium heterocarpon'', ''

Desmodium intortum ''Desmodium intortum'', known as greenleaf desmodium and also as beggarlice along with other members of its genus, is a species of flowering plant in the genus ''Desmodium'', native to Mexico, Central America, northern South America, the Galápag ...

'', and ''

Desmodium uncinatum ''Desmodium uncinatum'', the silverleaf desmodium, is a species of flowering plant in the family Fabaceae, native to Latin America, and introduced as a fodder to various locales in Africa, India, New Guinea, Australia and Hawaii. Although chief ...

'' are inter-cropped in

maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The ...

and sorghum fields to repel ''

Chilo partellus ''Chilo partellus'', the spotted stalk borer or spotted stem borer, is a moth in the family Crambidae. It was described by Charles Swinhoe in 1885. It is found in India, Pakistan, Iran, Ethiopia, Lesotho, Madagascar, Malawi, South Africa, Sudan, ...

'', a stem-boring

grass moth The Crambidae are the grass moth family of lepidopterans. They are variable in appearance, the nominal subfamily Crambinae (grass moths) taking up closely folded postures on grass stems where they are inconspicuous, while other subfamilies includ ...

, and suppress witchweeds, including Asiatic witchweed (''Striga asiatica'') and purple witchweed (''S. hermonthica''). High amounts of antixenotic

allomone An allomone (from Ancient Greek ' "other" and pheromone) is a type of semiochemical produced and released by an individual of one species that affects the behaviour of a member of another species to the benefit of the originator but not the rec ...

s produced by ''Desmodium'' also repel

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 ...

pests. Different ''Desmodium'' species produce different profiles of organic compounds through their root systems. The reasons for the production of these compounds that have benefited cereal crop production are however unknown. Tick-trefoils are also useful as living mulch and as green manure, as they are able to improve soil fertility via

nitrogen fixation Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmo ...

. Most also make good fodder for animals including bobwhite, turkey, grouse, deer, cattle and goats. Some ''Desmodium'' species have been shown to contain high amounts of

tryptamine Tryptamine is an indolamine metabolite of the essential amino acid, tryptophan. The chemical structure is defined by an indole ─ a fused benzene and pyrrole ring, and a 2-aminoethyl group at the second carbon (third aromatic atom, with the f ...

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

s, though many tryptamine-containing ''Desmodium'' species have been transferred to other genera. The caterpillars of the lesser grass blue (''Zizina otis'') and the two-barred flasher (''Astraptes fulgerator'') feed on tick-trefoils. Deer also appear to rely on some species in certain areas, particularly during the more stressful summer months.

Taxonomy and systematics

The

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

and systematics of the many dozens of ''Desmodium''

are confusing and unresolved. Related genera such as '' Codariocalyx'', '' Hylodesmum'', ''

Lespedeza ''Lespedeza'' is a genus of some 40 species (including nothospecies) of flowering plants in the pea family (Fabaceae), commonly known as bush clovers or (particularly East Asian species) Japanese clovers (''hagi''). The genus is native to warm t ...

'', '' Ohwia'', and '' Phyllodium'' were and sometimes still are included in ''Desmodium''.ILDIS (2005) Taxonomic authorities commonly disagree about the naming and placement of species. For example, '' Desmodium spirale'' as described by

August Grisebach August Heinrich Rudolf Grisebach () was a German botanist and phytogeographer. He was born in Hannover on 17 April 1814 and died in Göttingen on 9 May 1879. Biography Grisebach studied at the Lyceum in Hanover, the cloister-school at Ilfe ...

might refer to a distinct species, but its validity is doubtful. The "''Desmodium spirale''" of other authorities may refer to '' D. neomexicanum'', '' D. ospriostreblum'', or '' D. procumbens''. Similarly, the plant originally described as ''D. podocarpum'' by

A. P. de Candolle Augustin Pyramus (or Pyrame) de Candolle (, , ; 4 February 17789 September 1841) was a Swiss botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple of years de Candolle ...

is '' Hylodesmum podocarpum'' today, but "''Desmodium podocarpum''" might also refer to '' D. hookerianum'' or '' Hylodesmum laxum'', depending on the taxonomic authority.

Selected species

Species include: Ougeinia dalbergioides Bra23

* '' Desmodium acanthocladum'' F.Muell. * '' Desmodium canadense'' (L.) DC. – showy tick-trefoil, Canadian tick-trefoil * '' Desmodium canescens'' (L.) DC. – hoary tick-trefoil * '' Desmodium ciliare'' (Muhl.) DC. – hairy small-leaved tick-trefoil * ''

Desmodium cuspidatum ''Desmodium cuspidatum'', common name large-bracted tick-trefoil, is a species of plant in the legume family, Fabaceae. It is native to North America. Conservation status The species is listed as endangered in Connecticut by state authorities. ...

'' (Muhl.) Loudon – toothed tick-trefoil, large-bracted tick-trefoil * '' Desmodium glabellum'' (Michx.) DC. * '' Desmodium heterocarpon'' (Michx.) DC. – Asian tick-trefoil * ''Desmodium'' × ''humifusum'' (Muhl. ex Bigelow) Beck * '' Desmodium illinoense'' A.Gray – Illinois tick-trefoil * ''

Desmodium incanum :''The ''Desmodium incanum'' of many older sources is actually '' Desmodium laxiflorum''; see below.'' ''Desmodium incanum'', also known as creeping beggarweed, Spanish clover, Spanish tick-trefoil or hitchhikers is a perennial plant native to C ...

'' (Sw.) DC. – creeping beggarweed, Spanish tick-trefoil, Kaimi clover * ''

'' Greenleaf desmodium, kuru vine, beggarlice, tick clovers * '' Desmodium lineatum'' (Michx.) DC. – linear-leaved tick-trefoil * '' Desmodium marilandicum'' (L.) DC. – smooth small-leaved tick-trefoil * '' Desmodium ospriostreblum'' Chiov. * '' Desmodium paniculatum'' (L.) DC. – panicled tick-trefoil * '' Desmodium perplexum'' B.G.Schub. – perplexed tick-trefoil * '' Desmodium rhytidophyllum'' F.Muell. ex Benth. * '' Desmodium rotundifolium'' DC. – round-leaved tick-trefoil, dollar leaf * '' Desmodium triflorum'' (L.) DC. * '' Desmodium tweedyi'' Britton – Tweedy's tick-trefoil * ''

'' (Jacq.) DC.– silver-leaved tick-trefoil, silverleaf * ''

Desmodium varians ''Desmodium varians'' is a small climbing or prostrate herb in the family Fabaceae. A widespread species but not commonly seen, found in eastern Australia. Attractive pink flowers may form at any time of the year. The specific epithet varians i ...

'' (Labill.) G.Don

Formerly placed here

* '' Codariocalyx motorius'' – telegraph plant (as ''D. gyrans'', ''D. motorium'', ''D. roylei'') * '' Hylodesmum laxum'' (as ''D. laxum'' DC.) Lespedeza thunbergii2

** ''Hylodesmum laxum'' ssp. ''laxum'' (as ''D. austro-japonense'', ''D. bambusetorum'', ''D. gardneri'' auct. ''non'' Benth., ''D. laxiflorum'' ''sensu'' Miq., ''D. laxum'' var. ''kiusianum'', ''D. laxum'' ssp. ''laxum'', ''D. podocarpum'' auct. ''non'' DC. ''non'' Hook. & Arn., ''D. podocarpum'' DC. var. ''gardneri'' ''sensu'' Bedd., ''D. podocarpum'' DC. var. ''laxum'') * '' Hylodesmum leptopus'' (as ''D. gardneri'' Benth., ''D. laxum'' auct. ''non'' DC., ''D. laxum'' ssp. ''leptopus'', ''D. leptopus'', ''D. tashiroi'') * '' Hylodesmum podocarpum'' (as ''D. podocarpum'' DC., ''D. podocarpum'' DC. var. ''indicum'', ''D. podocarpum'' DC. var. ''japonicum'') ** ''Hylodesmum podocarpum'' ssp. ''oxyphyllum'' (as ''D. fallax'' var. ''mandshuricum'', ''D. japonicum'', ''D. mandshuricum'', ''D. oxyphyllum'' DC., ''D. podocarpum'' DC. var. ''mandshuricum'', ''D. podocarpum'' DC. ssp./var. ''oxyphyllum'', ''D. podocarpum'' DC. var. ''polyphyllum'', ''D. podocarpum'' DC. var. ''typicum'', ''D. racemosum'') * ''

Lespedeza thunbergii ''Lespedeza thunbergii'' is a species of flowering plant in the Fabaceae, legume family (biology), family known by the common names Thunberg's bushclover, Thunberg's lespedeza, and shrub lespedeza. It is native to China and Japan. This species p ...

'' (as ''D. formosum'', ''D. thunbergii'') ** ''Lespedeza thunbergii'' var. ''thunbergii'' (as ''D. penduliflorum'' Oudem.) * '' Ohwia caudata'' (as ''D. caudatum'') * '' Phyllodium pulchellum'' (as ''D. pulchellum'') * '' Dendrolobium umbellatum '' (as ''D. umbellatum'' (L.) Benth. * '' Dendrolobium triangulare '' (as ''D. Desmodium umbellatum'' Moritz.

References

* (2005)
Genus ''Desmodium''
Version 10.01, November 2005. Retrieved 2007-DEC-17.

External links

* Trout, K. (2002)
Trout’s Notes on the Genus ''Desmodium''.
Mydriatic Productions. Better Days Publishing. {{Taxonbar, from=Q258623 Forages Fabaceae genera