Trifolium is from the Latin tres meaning 3 and folium meaning leaf and refers to the 3 leaflets.
Cluster Clover.
Other names:
Ball Clover
Bush Clover
Flat headed Clover
McNeill Clover
Native Trefoil
Round head Clover
Smooth head Trefoil
Summary:
A hairless, low lying, trifoliate leaved annual legume with points on the leaflet edges where the veins stick out. It has pink flowers packed into a ball-like, "clustered", stalkless head in spring to early summer.
Native to western and southern Europe, it flowers in winter and spring.
Description:
Cotyledons:
Two. Oval. Hairless. Rounded tip. Sides convex. Base tapered to squarish. Surface hairless. Petiole shorter than the blade.
First leaves:
First leaf is round with a flat base, hairless with slightly scalloped edges and on a long petiole. Second leaf is hairless with a long petiole with three oval leaflets with prominent veins ending in pointed teeth.
Leaves:
Alternate. 3 leaflets on equal very short stalks that may have a few hairs.
Stipules - 8-10 mm long. The free section narrowly egg shaped with a long tapering tip. Prominent nerves.
Petiole - Slender. Upper leaves have a very short petiole.
Blade - Leaflets, egg shaped to triangular, 6-22 mm long by 3.5-11 mm wide. Distinct veins that end in sharp lobes or teeth on the edge of the leaflet. Tip rounded, flat or slightly notched. Surface hairless with white markings.
Stems:
Low lying or upward bending, up to 300 mm long. Hairless.
Flower head:
Arise from most leaf axils, no stalk, many flowered, globular, 8-12 mm diameter. Surrounded by broadly egg shaped, membranous floral stipules but not embraced by them.
Flowers:
Pink, narrow, pea type, stalkless.
Ovary -
Calyx - 3-5 mm long, tubular. Tube is white, striped, 2-3 mm long. Hairless. 10 prominent veins with a hairless throat. 5 almost equal lobes, egg shaped, 1.5-2 mm long, rigid, bent back with a tapering tip and shortly awned. Stiff and spreading when in fruit.
Petals - Narrow, pink, 5-6 mm long, narrow. Limb of standard narrowly oblong to egg shaped, folded lengthwise with a blunt or toothed tip. Standard longer than calyx. Keel slightly shorter than the wings with an obtuse tip.
Stamens - 10 with 9 in a group.
Anthers -
Fruit:
Oblong pod, 2-3 mm long. Hidden in persistent calyx. 1-2 seeds per pod.
Seeds:
Yellowish brown, almost globular, 1mm wide. Surface smooth, dull, dimpled, grooved and hairless.
Roots:
With nitrogen fixing nodules.
Key Characters:
Heads sessile, small, in leaf axils. Flowers pink, sessile. Standard pink, longer than calyx. Calyx 10 nerved, teeth finally spreading or recurved, throat open. Pod 1-2 seeded, enclosed in calyx. Leaflets obovate-cuneate, teeth not glandular. Stipules small. Annual. Hairless.
Biology:
Life cycle:
Annual. Seeds germinate in autumn to winter. It is grows well during autumn winter and spring and flowers from September to December. With to onset of high summer temperatures and drought it dies.
Physiology:
Has symbiotic rhizobia in nodules in the roots that fix atmospheric nitrogen.
Relatively drought tolerant.
Reproduction:
By seed.
Flowering times:
Spring to early summer in western NSW.
October to December in SA.
September to November in Perth.
Spring in WA.
Seed Biology and Germination:
Sets large amounts of seed, even under grazing, with a high proportion of dormant hard seed.
Vegetative Propagules:
None.
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
South western Europe.
Distribution:
ACT, NSW, QLD, SA, TAS, VIC, WA.
Habitats:
Climate:
Temperate. Mediterranean.
Soil:
Prefers neutral to acid soils.
Low lying areas and drainage lines.
Plant Associations:
Many.
Significance:
Beneficial:
Palatable fodder.
Detrimental:
Weed of lawns, gardens, cultivated areas, pastures, crops, swamps, granite outcrops, roadsides, bushland and disturbed areas.
Toxicity:
May cause "yellows" in sheep.
Legislation:
None.
Management and Control:
Dicamba and sulfonylurea herbicides provide good control.
Thresholds:
Eradication strategies:
Prevent seed set for 5 years.
Exclude stock to prevent dispersal of seed and burrs.
Hand pull isolated plants in winter before flowering. For small infestations and grass dominant areas an annual application of 10 mL Tordon®75-D in 10 L water in early winter gives excellent control of existing plants and has residual activity to control seedlings.
In bushland, 200 g/ha Lontrel®750 or 50 g/ha Logran® applied in early winter provides reasonably selective control. Use 25 mL wetting agent plus 4 g Lontrel®750 or 1 g Logran® or 0.1 g metsulfuron(600g/L) or 0.1 g chlorsulfuron(750g/kg) in 10 L water for hand spraying when they are actively growing. Repeat annually for several years. Plant tall growing perennial species to reduce re-invasion.
Clovers are relatively tolerant to glyphosate, grazing and mowing.
Herbicide resistance:
Biological Control:
Related plants:
Alsike Clover (Trifolium hybridum)
Arrowleaf Clover (Trifolium vesiculosum)
Balansa Clover (Trifolium balansae)
Berseem Clover (Trifolium alexandrinum)
Birdsfoot Trefoil (Trifolium ornithopodioides)
Bladder Clover (Trifolium spumosum)
Caucasian Clover (Trifolium ambiguum)
Cluster Clover, Ball Clover (Trifolium glomeratum) is a ground-hugging plant with broad leaflets, 5-22 mm long, and globular heads of pink flowers.
Crimson Clover (Trifolium incarnatum)
Cupped Clover (Trifolium cherleri)
Drooping flowered Clover (Trifolium cernuum)
Gland Clover (Trifolium glandulosum)
Globe Clover (Trifolium globosum)
Hop Clover(Trifolium campestre) is a sprawling plant with fairly broad leaflets, 4-15 mm long, and globular to ovoid heads of yellow flowers. The standard petal is not furrowed and it has 20-50 flowers in the head.
Hare's Foot Clover(Trifolium arvense) is an erect or sprawling plant with narrow leaflets 5-20 mm long and ovoid to shortly cylindric heads of white or pink flowers.
Kenya White Clover (Trifolium semipilosum)
Knotted Clover (Trifolium striatum)
Lappa Clover (Trifolium lappaceum)
Ligurian Clover (Trifolium ligusticum)
Narrow-leaved Clover (Trifolium angustifolium) is an erect plant with long narrow leaflets, 15-75 mm long, and cylindric heads of pink flowers.
Purple Clover (Trifolium purpureum)
Red Clover (Trifolium pratense)
Rose Clover(Trifolium hirtum) is a hairy plant with fairly broad leaflets, 10-25 mm long, and globular to semi-globular heads of pink to purple flowers.
Rough Clover (Trifolium scabrum)
Sea Clover (Trifolium squamosum)
Shaftal Clover (Trifolium resupinatum)
Slender Suckling Clover (Trifolium micranthum)
Star Clover (Trifolium stellatum)
Strawberry Clover (Trifolium fragiferum)
Subterranean Clover (Trifolium subterraneum) is a ground-hugging plant with broad leaflets, 6-22 mm long, and few-flowered heads of white flowers that form globular buried burrs.
Suckling Clover(Trifolium dubium) is a sprawling or ground-hugging plant with fairly broad leaflets, 4-12 mm long, and loose globular heads of yellow flowers.
Suffocated Clover (Trifolium suffocatum)
White Clover (Trifolium repens) is a ground-hugging plant with broad leaflets, 4-12 mm long, which often have a pale v-shaped band and globular heads of white flowers.
Woolly Clover(Trifolium tomentosum) is a sprawling plant with broad leaflets, 4-13 mm long and globular heads of pink flowers which become woolly with age.
Zigzag Clover (Trifolium medium)
Trifolium strictum
Plants of similar appearance:
Medics, Trefoils, Oxalis spp.
References:
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P453. Diagram.
Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P222.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P426. Photo.
Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P160. Photo.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #1228.12.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P303.