Desmanthus bicornutus


Scientific name

Synonyms

Acuan subulatum Britton & Rose
Acuan bicornutus (S. Watson) Britton & Rose
Mimosa canonis M.E. Jones, Leafl.
Desmanthus subulatus (Britton & Rose) Wiggins ex B.L. Turner
Desmanthus rostratus B.L. Turner

Family/tribe

Family: Fabaceae (alt. Leguminosae) subfamily: Mimosoideae tribe: Mimoseae.  Also placed in: Mimosaceae.

Common names

malvilla de laguna (Mexico).

Morphological description

Small erect shrub 1.5-3 m tall, woody at the base, unbranched or with 2-3 branches from the base.  Woody, cylindrical, branched taproot to 70 cm long.  Young stems hairless, often deep red in colour, 4-angled, stem -base with smooth, light brown bark.  Older stems hairless, shiny red or brown. 
Compound bipinnate leaf 9-18 cm long with 6-14 pairs of pinnae 15-46 mm long and 20-45 pairs of leaflets/pinnae 2.7-5.4 mm long and 0.7-1.3 mm wide.  Persistent stipules 3-6 mm long, sometimes deciduous with age.
Small flowering heads (condensed spikes) 0.8-1.7 cm long, occur singly or in pairs in leaf axils on short peduncles 1.5-3.7 cm long.  Heads contain 25-60 flowers that may be perfect, functionally male or sterile.  8-20 white or pale green sterile flowers occur at the base of the head.  Male flowers occur towards the base of the head above the sterile flowers, but below the perfect flowers and number 0-6.  Perfect flowers (16-40) occur apically.  Of these, 6-20 are functionally perfect and the remainder are functionally male because the style fails to elongate.  Fruiting stalks 1.5-5.0 cm long bear 2-12 pods.
Pods are linear , 4.6-10 cm long and 2.7-4.5 mm wide, opening along both margins.  Red when immature, dark-brown at maturity.
Seeds 7-22/pod, 2.5-3.7 x 2.0-2.8 mm, ovate to rhomboid in shape and brown in colour.

Distribution

Native to:
Occurs from southern Arizona, USA, through the northern Mexican states of Baja Sur, Chihuahua, Sinaloa, Sonora and the central Mexican states of Colima, Guerrero, Jalisco, Michoacan, Nayarit, Veracruz, at 0-1,400 m asl along washes, roadsides, canyons and watercourses at lower elevations and in oak woodland or grassland areas at higher elevations.

Uses/applications

A component of grazed grasslands in northern Mexico and southern Arizona, USA.  Seeds are eaten in a salsa in Guerrero, Mexico.  Has potential as a legume component of sub-humid grasslands under grazing.

Ecology

Soil requirements

Occurs on sandy, rocky and clay soils in the native range.

Moisture

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Occurs over a wide annual rainfall range from 300 mm in Arizona, USA to 1,300 mm, occasionally to 2,000 mm in coastal, southeast Mexico.  These environments have intense dry seasons of 3-10 months in duration.

Temperature

Average annual temperatures are also highly variable from 20°C in Arizona, USA, with a range of 11-32°C for the coldest and hottest months respectively, to 25.5°C in southeast Mexico, with a range of 20-30°C for the coldest and hottest months respectively.

Light

May possess some shade tolerance, being an understorey component of a range of scrub, forest and woodland types.

Reproductive development

Flowering occurs August to November and fruiting occurs predominantly September to December in the native range (Mexico, southern USA, 18-32°N).

Defoliation

Tolerant of regular heavy grazing pressure .

Fire

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Will regrow after fire.

Agronomy

Establishment

No information is available specifically for D. bicornutus , but information for D. virgatus is relevant.  Sow 1–2 kg/ha of scarified seed at a depth of 0.5–2.0 cm into moist soil with at least 50–60 cm depth of good moist soil to ensure establishment.  Deeper planting depths may prevent or delay emergence.  Surface broadcasting onto a well-prepared seedbed, followed by rolling, or planting using a “crocodile” seeder have also given good results.  Has been established successfully into cultivated strips, or sod-seeded into slashed back pasture treated with glyphosate to suppress grass growth.

Fertiliser

No information available.

Compatibility (with other species)

Some accessions compatible with buffel and native grasses of western Queensland and other accessions compatible with tall native grasses on the wet/dry tropical coast of northern Queensland.

Companion species

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Grasses:  Black spear grass (Heteropogon contortus ), kangaroo grass (Themeda triandra), buffel grass (Cenchrus ciliaris ).

Pests and diseases

No information available.

Ability to spread

Has not spread from 14 year old trial plots in western Queensland.

Weed potential

An abundant roadside weed across its native range, D. bicornutus has considerable potential to colonise disturbed areas.

Feeding value

Nutritive value

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Unknown.  Probably similar to D. virgatus .

Palatability/acceptability

In semi-arid western Queensland grazed to ground level.

Toxicity

No information available.

Production potential

Dry matter

CPI 91162 yield >6 t/ha.

Animal production

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Unknown.  Probably similar to D. virgatus .

Genetics/breeding

Not currently used in any breeding programs.

Seed production

CPI 91162 produces large amounts of seed.  CPI 90857 also a good seed producer (no data).  CPI 90013A is reported to have good seed yields at Walkamin.

Herbicide effects

Killed by Access® herbicide (120 g/L picloram and 240 g/L triclopyr).

Strengths

  • Well-adapted to strongly seasonally dry sub-humid environments.
  • Tolerant of alkaline, sodic, saline and heavy clay soils.
  • Drought tolerant.
  • Grazing tolerant.

Limitations

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  • Recruitment in the years following planting is limited by hardseededness .
  • Highly specific in its rhizobium requirements.

Other comments

    

Selected references

Gardiner C.P. and Burt R.L. (1995) Performance characteristics of Desmanthus virgatus in two contrasting tropical environments.Tropical Grasslands, 29, 183-187.
Hopkinson, J.M. and English, B.H. (2004) Germination and hardseededness in Desmanthus. Tropical Grasslands, 38, 1-16.
Luckow, M. (1993) Monograph of Desmanthus (Leguminosae-Mimosoideae). Systematic Botany Monographs. Vol. 38. The American Society of Plant Taxonomists.
Ocumpaugh, W.R., Grichar W.J., Hussey Jr M.A., Abrameit A.H., Owens, M.K., Reed R.L,  Muir J.P., Bade D. and Reilley J.L. (2004) Registration of "BeeTam 06". Crop Science, 44.
Pengelly, B.C. and Liu, C.J. (2001) Genetic relationships and variation in the tropical mimosoid legume Desmanthus assessed by random amplified polymorphic DNA. Genetic Resources and Crop Evolution, 48, 91-99.

Internet links

Cultivars

Cultivars

Country/date released

Details

'BeeWild' USA (2004) 'BeeWild" is the commercial form of a mechanical blend of four released cultivars in Texas, USA - 'BeeTAM-06', 'BeeTAM-08', 'BeeTAM-37', 'BeeTAM- 57' which have better adaption to certain sites and flower at slightly different times. These cultivars are being used as forage for deer and wildlife habitat.  See Ocumpaugh et al. 2004.

Promising accessions

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Promising accessions

Country

Details

CPI 91162 Australia Productive shrub in wet/dry tropics of northeastern Queensland, AAR 1,200 mm.  Has persisted in trial plots in shaded Eucalypt woodland savannah for 10 years.  Regrew after fire.  Good seed production.
CPI 90857 Australia CPI 90857 is showing great potential and drought tolerance in semi-arid AAR 450 mm area of northwestern Queensland on pebbly clay soils.