Stinking Roger Osteospermum clandestinum (Less.) Norlindh
Synonyms - Tripteris clandestina
Family: - Asteraceae.
Names:
Osteospermum is from the Greek osteos meaning bone and sperma meaning seed and refer to the hard or bony seeds.
Clandestinum means hidden.
Stinking Roger.
Summary:
An aromatic, erect, annual herb to 50 cm that is usually sticky to touch and has yellow and red-brown flowers from winter to spring that droop with age.
Description:
Cotyledons:
Two.
Leaves:
Alternate.
Stipules -
Petiole - Short on lower leaves, upper ones clasp the stem.
Blade - Elliptical to egg shaped, up to 100 mm long by 15 mm wide, sticky to touch, edges with rounded lobes. Acute or obtuse tip. Glandular hairs.
Stem leaves - Upper ones usually without lobes.
Stems:
Erect, up to 500 mm tall. Glandular hairs, sticky to touch.
Flower head:
Single flowers on long stalks at ends of several branches. Initially erect and droop with age. 8-13 egg shaped to oblong, free, leafy bracts with broad papery edges and an obtuse tip in 1 row. Bell shaped base or involucre, 5-20 mm diameter.
Flowers:
Yellow and brown with a dark red to greenish centre.
Ray (outer) flowers female, dark brown tube with yellow and brown ligules or 'petals'. As long as to 1.5 times as long as the bracts.
Ovary - Style not divided at the tip.
'Petals' - 8, yellow petals with a dark brown, reddish or dark blue centre.
Disc flowers male, greenish, about 10, tubular, 5 lobed, bisexual but sterile.
Stamens -
Anthers - Tiny awn at the base of each lobe
Fruit:
Fruits enclosed by expanded bracts of the flower head.
Achene, 8.5-10 mm long by 3.5-8.5 mm wide with 3, broad, papery, vertical wings. Outer face is smooth to wrinkled with spiny growths. They have a have a hollow chamber with a single window on the outer face above the ovary.
Seeds:
10mm with 3 vertical wings.
Roots:
Taproot.
Key Characters:
Involucre bracts lanceolate-acute with broad scarious margins. Ray achenes uniform, 3 winged.
Biology:
Life cycle:
Annual. Germinates autumn/winter. Flowers in May-October.
Physiology:
Reproduction:
By seed.
Flowering times:
August to October in SA.
July to October in Perth.
May to October in WA.
Seed Biology and Germination:
Vegetative Propagules:
None.
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
South Africa.
Distribution:
SA, VIC, WA.
Habitats:
Climate:
Temperate. Mediterranean.
Soil:
Plant Associations:
Significance:
Beneficial:
Virtues undiscovered.
Detrimental:
Weed of crops, pastures, roadsides, wet areas, granite outcrops, open bushland and wastelands.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
Thresholds:
Eradication strategies:
Herbicide resistance:
Biological Control:
Related plants:
Osteospermum calendulaceum is smaller, more spreading and with yellow petals and unwinged fruits and occurs in drier areas.
Osteospermum fruticosum is perennial.
Plants of similar appearance:
References:
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P889-890. Diagram.
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). P102. 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). #916.2.
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). P695. Diagram.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.