Australian Buttercup

Ranunculus lappaceus Smith

Synonyms - Ranunculus colonorum.

Family: Ranunculaceae.

Names:

Ranunculus is Latin for tadpole from the Latin rana meaning frog and may refer to the damp habitats preferred by many species in this genus.
Australian Buttercup because it is an Australian native with rich yellow, butter coloured, cupped type flowers.

Other names:

Buttercup
Common Buttercup.

Summary:

A softly hairy, erect perennial herb up to 600 mm high with bright yellow flowers and 3 segment, divided leaves.

Description:

Cotyledons:

Two.

Leaves:

Alternate. Forms a rosette.
Stipules - None.
Petiole - 50-180 mm long, with papery, clasping, sheathing bases.
Blade - Egg to wedge shaped in outline. 15-80 mm long. Divided in sets of 3, toothed lobes or 3 stalked segments. Each segment usually has 3, toothed lobes or is deeply divided. Hairy.
Stem leaves - Fewer, much smaller with narrow lobes or narrow oval shaped. Hairy.

Stems:

Usually erect, 20-600 mm high, branched. With dense, spreading hairs.

Flower head:

2-8 flowers per stem on long erect stalks.

Flowers:

Yellow, 20-40 mm wide.
Ovary - 20-45 carpels. One ovule per carpel. Short style. Receptacle, hairy and oblong.
Sepals - 5 egg shaped to oblong-oval, 4-8 mm long, spreading, overlapping. Hairy on outer surface. Bend back with age. Fall off early.
Petals - 5 yellow, broad, smooth and shiny, egg shaped to triangular, 9-25 mm long with nectar pit at the base. Obtuse tipped. Nectary lobe, wedge shaped, broader than long.
Stamens - Many, 40-60.
Anthers -

Fruit:

Globular cluster of achenes. Achenes, flattened, egg shaped in outline. 2-5 mm long x 2.5-4 mm wide, smooth, edges ridged. Hairless. Slender, narrow curved or coiled beak, 1-2 mm long.

Seeds:

Enclosed in fruit(achene).

Roots:

Taproot

Key Characters:

Leaves alternate or radical with broad, flat lobes, mainly radical, stem leaves smaller.
Stems leafy, branched to 600 mm high.
Flowers regular, not spurred, 20-40 mm across.
Petals yellow, broadly obovate to cuneate.
Sepals spreading.
Nectary lobe cuneate and broader than long.
Achenes smooth in a globular head and hairless with rigidly curved, 1-2 mm long beaks.
Style of achene becoming a short beak.
Stolons absent.
Villous.
Tufted perennial land plant.
From J.M. Black, N.T. Burbidge and J.R. Wheeler.

Biology:

Life cycle:

Annual stem, perennial rootstock. Flowers July to December. Grows mainly in winter and spring and top growth dies in summer. New season growth emerges from rootstock in autumn.

Physiology:

Reproduction:

By seed.

Flowering times:

Spring and summer in western NSW.
July to December in SA.
September to December in Perth.

Seed Biology and Germination:

Vegetative Propagules:

Hybrids:

Ranunculus lappaceus and Ranunculus colonorum are very similar and often confused. In Ranunculus colonorum the petals are narrower and the sepals turned downward, rather than erect or spreading and it is more common in WA whereas Ranunculus lappaceus is more common in the eastern states.

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed.
More abundant in very wet years.

Origin and History:

Australia.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Wet areas.

Climate:

Temperate. Mediterranean.

Soil:

Often on clay soils.

Plant Associations:

Sclerophyll forests to alpine woodlands and swamps.
Black Box and River Red Gum.

Significance:

Beneficial:

Fodder. More palatable to cattle than sheep.

Detrimental:

Weed of poorly drained pastures and disturbed areas.

Toxicity:

Sap constituent, protoanemonin, can cause colic and inflammation in animals. Bitter taste usually deters grazing.
May cause blindness in horses.
Can cause skin dermatitis in humans.

Symptoms:

Blindness.

Treatment:

Remove stock from infested areas.

Legislation:

None in WA.

Management and Control:

Thresholds:

Eradication strategies:

Herbicide resistance:

Relatively tolerant to glyphosate.

Biological Control:

Related plants:

Celery Buttercup (Ranunculus sceleratus)
Corn Buttercup (Ranunculus arvensis)
Creeping Buttercup (Ranunculus repens) is very similar but has long stolons and the beaks of the achenes are less curved and almost erect.
Large Annual Buttercup (Ranunculus trilobus)
Pale Hairy Buttercup (Ranunculus sardous)
River Buttercup (Ranunculus inundatus)
Sharp Buttercup (Ranunculus muricatus)
Small flowered Buttercup (Ranunculus parviflorus)
Small flowered Buttercup (Ranunculus pumilio)
Small flowered Buttercup (Ranunculus sessiliflorus)
Small River Buttercup (Ranunculus amphitrichus)
Smooth Buttercup (Ranunculus pentandrus)
Snakes tongue Buttercup (Ranunculus ophioglossifolius)
Swamp Buttercup (Ranunculus undosus)

Plants of similar appearance:

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P211-212. Photo.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P363. Diagram of seed.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P171-175. Diagram.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P309. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P600.

Gardner, G.A. and Bennetts, H.W. (1956). The toxic plants of Western Australia. (West Australian Newspapers Ltd, Perth). P29.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne). P232.

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #1043.4.

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). P66.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.