Senecio is from the Latin senex meaning old man and refers to the beard like pappus on the seed.
A fleshy stemmed, erect, annual herb with terminal clusters of small, yellow, nodding flowers without 'petals' from July to February and leaves that are deeply lobed and lobes that are toothed.
Two. 6 to 13 mm long overall. Tip rounded. Sides convex. Base tapered. Surface hairless. Petiole hairless, 2 to 4 mm long, shorter than the blade and merging with it. The plant has a long hypocotyl and a short epicotyl.
The leaves develop singly, the first being 15 to 25 mm overall in length and sessile or with a merging petiole. The earliest leaves may have a few or no hairs. The first leaf usually has a few small lobes.
Alternate. Does not form a rosette.
Petiole - On the lower leaves only.
Blade - 20-100 mm long by 5-45 mm wide, many deep lobes, leaf edge flat. Lobes oblong with wavy teeth and rounded tips, the end lobe tends to be larger than the side lobes. Numerous multi-cellular hairs on the upper and lower leaf surface or restricted to veins of the lower surface or hairless.
Stem leaves - stalkless and often partially stem clasping with lobes at the base, 50 to 75 mm long, and practically hairless or with a scattering of multi-cellular hairs on the upper and lower surfaces.
150-750 mm tall, fleshy, weak, may branch but small plants are often single stemmed, polygonal in cross section, solid, and carry multi-cellular hairs which look like minute strings of beads under magnification or are hairless.
Terminal or axillary in dense clusters(corymbs), initially stalkless and later carried on short stems. Flower base(involucre) cylindrical, cup shaped, 5-12 mm long by 4-10 mm diameter with 15-21 bracts.
Bracts - Green, narrowly egg shaped. Short outer bracts in 2-3 rows. Tips are black, pointed and hairy.
Florets - Many, scarcely longer than the flower base(involucre), short, yellow, no 'petals', tubular, bisexual.
'Petals' - None.
Greyish, hairy, striped, cylindrical achene, 1.5-2.5 mm long by 0.2-0.4 mm wide with short, low lying hairs in vertical lines. Pappus of many, white, fine, hairs that are as long or longer than the florets (or twice as long as the achene).
Enclosed in the fruit.
Leaves obovate, irregularly toothed to pinnatifid into lanceolate or oblong-toothed lobes, sparsely simple hairy or glabrous. Ultimate lobes obtuse and without callose apices.
Involucre cylindrical, 7-9 mm long.
Flower heads homogamous-discoid.
Florets scarcely longer than involucre, all tubular, all bisexual, yellow.
Achenes not attenuate towards the summit and up to 2 mm long.
From J.M. Black, N.T. Burbidge and N.S. Lander.
Annual. Germination occurs in the autumn or spring.
July to November in SA.
July to October in Perth.
July to February in WA.
Seed Biology and Germination:
WA specimens are subspecies vulgaris.
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Distributed throughout Tasmania.
Most abundant on sandy soils
Weed of gardens, lawns, crops, cultivation, summer irrigated vegetables, shore lines and disturbed areas.
It is of usually of little economic significance.
Possibly toxic but no field case have been reported in Australia.
Management and Control:
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.
African Daisy (Senecio pterophorus)
Bushy Groundsel (Senecio cunninghamii)
Canary Creeper (Senecio tamoides)
Cape Ivy (Senecio angulatus)
Cape Ivy (Senecio mikanioides = Delairea odorata)
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)
Plants of similar appearance:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P114. Diagram.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P887. Diagram.
Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P372.
Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P183.
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). P104-105. Photo.
Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P40-41. 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). #1125.21.
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). P705.
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.