African Daisy

Senecio pterophorus DC.

Family: Asteraceae.

Names:

Senecio is from the Latin senex meaning old man and refers to the beard like pappus on the seed.
Pterophorus is from the Greek pteron meaning wing and phoros meaning bearing and refers to the wings on the petioles that extend down the stems.
African Daisy refers to its origin and its Daisy type flowers.

Other names:

Perdegifbos (South Africa)
South African Daisy
Winged Groundsel.

Summary:

A bushy, perennial shrub, usually about 1000 mm tall with toothed leaves and large, flat topped clusters of yellow, daisy like flowers at the ends of the branches in summer.

Description:

Cotyledons:

Two.

Leaves:

Alternate.
Petiole - Winged and on lower leaves and stem clasping with the wings continuing down the stem.
Blade - Variable, narrowly egg shaped and may have coarsely toothed margins, 50-150 mm long x 5-25 mm wide, leathery, dark green and almost hairless on the upper surface and white with woolly hairs on the underside. Tapering into the petiole.
Stem leaves - Narrower and without a petiole.

Stems:

Grey-green, erect, up to 3000 mm tall and usually about 800-1500 mm tall, many branched, stout, soft and sappy when young and becoming woody with age, lengthwise striped, ribbed and carry cobwebby, fine, woolly hairs or can be almost hairless. Wings on the lower stems.

Flower head:

Many flowers in a flat topped, corymbose panicle. Flower base (involucre) bell shaped, 4-4.5 mm diameter with 18-22 inner bracts, 4-5 mm long and 12-18 outer bracts. Hairless to sparsely cobwebby.

Flowers:

Composite (Daisy like) with 9-13 yellow ligulate ('petal') florets round the margin of the 'flower'. 'Petals' (ligules) 4-6 mm long.
Bracts - 18-22 inner bracts, oblong with brown, pointed, hairy tip. Outer bracts are similar but smaller.
Ovary - Flat receptacle with a honey comb like surface with the edges forming tiny scales.
Florets - Ray florets, 10-12 with 4-7 mm long, yellow petals (ligules). Disk florets, 40-95, darker yellow, tubular, bisexual.
'Petals' - 10-12, yellow, 4-7 mm long.
Stamens -
Anthers -

Fruit:

Red to dark brown, 1.5-2 mm long achene, oblong to cylindrical, ribbed, rough to touch due to tiny bristles. Pappus of silky hairs, 5 mm long, weakly attached to achene.

Seeds:

Enclosed in fruit.

Roots:

Fibrous, shallow, usually less than 200 mm deep, much branched, extending for about 3000 mm horizontally.

Key Characters:

Erect perennials.
Stems often woody towards the base.
Leaves glabrous above, white woolly below, linear to lanceolate, entire or toothed.
Heads comparatively small.
Involucre campanulate, 4-8 mm long.
Flower heads heterogamous-radiate.
Ligules yellow, spreading and conspicuous.
Adapted from J.M. Black.

Biology:

Life cycle:

Perennial. Seeds germinate mainly in autumn after the first rains for the season. Early growth is rapid and stems form from July and rapidly elongate. Flowering starts in late spring and continues through the summer until autumn. Seeds ripen 2-3 weeks after flowering. Growth slows in autumn and new shoots are produced from the perennial crown after autumn rains. Individual plants may survive for 7-10 years.

Physiology:

Grow rapidly and may reach a height of 3000 mm tall x 2000 mm wide in 2 years.

Reproduction:

By seed and a perennial crown.

Flowering times:

Summer in NSW.
Summer in SA.

Seed Biology and Germination:

Seed production is around 50,000 seeds per plant.
Requires light, germination levels drop at about 25% in full sun.
Little dormancy.
Optimum temperature for germination about 160C.

Vegetative Propagules:

Perennial crown.

Hybrids:

Prior to 2006, 2 varieties were recognised: Senecio pterophorus var. verus with wings on the petiole and Senecio pterophorus var. apterus with no wings on the petiole. These have both been regrouped into Senecio pterophorus DC. and are no longer current.
It forms hybrids with at least 3 native Senecio species, These hybrids have all been sterile.

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed that is blown in the wind, carried by water, animals and on vehicles and machinery or in mud. Most seed will probably fall close to the parent plant because the pappus readily breaks from the seed.
Some has been spread as a contaminant in soil used for road making and in agricultural produce.
It quickly invades areas that have been cleared or burnt.

Origin and History:

South Africa.
Introduced to SA around 1930 in ships ballast.
Found in Victoria in 1985.

Distribution:

NSW, SA and VIC.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate. Humid and sub humid sub tropical areas. Warm temperate savannas.
Most abundant in areas with an annual rainfall greater than 500 mm.

Soil:

Most abundant on the light to medium soils.

Plant Associations:

Savannah.

Significance:

Beneficial:

Ornamental.

Detrimental:

Weed of unimproved land, roadsides, denuded areas, crops, pastures, urban bushland and disturbed areas.
In SA this plant has been found to be invasive in conservation areas around Adelaide.
Grows vigorously on burnt areas.
Unpalatable and rarely grazed.
It is very competitive in crops and pastures.

Toxicity:

Toxic in feeding tests but field cases may be uncommon due to its unpalatable nature. Toxicity is most likely in contaminated hay or feeds.

Legislation:

Noxious weed of TAS and VIC.
Secondary and prohibited weed in Tasmania.

Management and Control:

Cultivate then plant competitive pastures. Slash as necessary to allow pasture to establish.
Graze heavily with goats or sheep in areas that can't be cultivated.
A number of herbicides provide good control in various situations. High volume misting is often used in difficult areas.

Thresholds:

Eradication strategies:

Manually remove isolated plants and their roots, to a depth of 200 mm, and spray a buffer area of 20 metres around the infestation with 1 part of Tordon® 75-D in 100 parts of water in early winter.
Prevent seed set.

Herbicide resistance:

Biological Control:

Related plants:

Bushy Groundsel (Senecio cunninghamii)
Canary Creeper (Senecio angulatus = S. tamoides)
Cape Ivy (Senecio mikanioides = Delairea odorata)
Common Groundsel. (Senecio vulgaris)
Commonwealth weed (Senecio bipinnatisectus)
Cotton Fireweed (Senecio quadridentatus)
Feathery Groundsel (Senecio anethifolius)
Fireweed (Senecio lautus)
Fireweed Groundsel (Senecio linearifolius)
Fleshy Groundsel (Senecio gregorii)
Hispid Fireweed (Senecio hispidulus)
Holly-leaved Senecio (Senecio glastifolius)
Mountain Fireweed (Senecio gunnii)
Purple Groundsel (Senecio elegans)
Ragwort (Senecio jacobaea)
Slender Groundsel (Senecio glossanthus)
Squarrose Fireweed (Senecio squarrosus)
Tall Groundsel (Senecio runcinifolius)
Tall Yellowtop (Senecio magnificus)
Senecio daltonii
Senecio madagascariensis
Senecio megaglossus

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). P113. Diagram.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P885.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P182-183.

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 3. P312. Diagram.

Hyde-Wyatt, B.H. and Morris, D.I. (1980) The Noxious and Secondary Weeds of Tasmania. (Tasmanian Department of Agriculture, Hobart, Tasmania). P94-95. Diagrams.

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). #1125.7.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P306-308. Photos.

Acknowledgments:

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