Hypochoeris radicata L.
catsear, common catsear, flatweed, false dandelion, long-rooted catsear, hawkweed, rooted catsear, dandelion
A native of Europe, Asia and North Africa
It is a perennial herb that grows from 15 to 80cm in height. A rosette-forming herb (a cluster of leaves at the base of a plant often lying flat against the ground) with shallowly divided leaves lying flat on the ground. The stems are erect with a yellow, terminal flower.
It is found most commonly in cooler to temperate areas of Australia. Often found in drier areas as its deep taproot tends to give it drought resistance. It tolerates a wide range in soil types, texture and pH. Grows mainly on sandy to sandy clay loam red and red brown earths; also on shallow stony soils of hillsides, less frequent on grey clay soils. It does not however tolerate poorly drained soils. It is most often found in pastures, cultivation, lawns, fallow paddocks, disturbed areas, roadsides and waste places.
Stems and Leaves:
The first leaves (cotyledons) are club-shaped, with a round apex, and hairless. The mature leaves grow to 15 to 20cm long. The leaves are arranged in a basal rosette and are hairy with toothed or irregularly lobed margins. The basal leaves are obovate in shape and are 5-20cm long and 10-40mm wide with toothed margins that are deeply wavy. The basal leaves are also densely hairy, rarely glabrous (without hairs or scales), and are sessile (without a stalk). The upper leaves if present are similar and reduced in size as they go up the stem. Leaves emit a milky sap when broken. It has leafless flower stalks (scapes) with 2 to 7 flowers on each stalk. The flower stalks also emit a milky sap when broken.
Flowers and Fruit:
The flowerheads (capitula) are solitary on branched stems. The flowerheads are up to 5-15mm in diameter with bracts 2.5cm long and yellow ligulate florets. The achene (a dry indehiscent 1-seeded fruit) is orange-brown and is 4-7mm long, has fine, toothed ribs and a long slender beak 7-10mm long that carries two rows of pappus (hairs) that are 8-14mm long which aid in dispersal by wind. Flowers spring-autumn.
The rosette growth habit, irregularly lobed leaves, and bright yellow flowers are all characteristics that help with the identification of common catsear. Dandelion (Taraxacum officinale) resembles catsear but has an unbranched hollow flower stalk (peduncle) much more divided leaves with the tips of the lobes pointing towards the base of the leaf and the flowerheads borne singly at the ends of the long, unbranched, leafless stalks (scapes) arising from the centre of the rosette. Crepis capillaris (L) Wallr (smooth hawkesbeard) can also be distinguished from Hypochoeris radicata in that Hypochoeris radicata has unbranched and/or slightly branching stems whereas Crepis capillaris has grooved stems that are branched from the base or above and upper leaves that are stem clasping. Hypochoeris radicata has obviously hairy leaves. Furthermore, the pappus is mounted on a long slender beak on all seeds whereas Hypochoeris glabra (smooth catsear) occurs in similar habitats but the leaves are generally hairless but sometimes have short, rigid marginal hairs or with sparse, coarse hairs on the upper surface and along the lower midrib. The outer most seeds do not have a beak so the pappus is directly attached to the seed. The pappus of the inner seeds is usually on a long beak.
Sources & References
Auld BA, Meld RW (1992) 'Weeds an illustrated botanical guide to the weeds of Australia.' (Inkata Press: Melbourne)
Cunningham GM, Mulham PL, Leigh JH (1981) 'Plants of Western New South Wales.' (NSW Government Printing Office: Australia)
Harden GJ (Ed) (2002) 'Flora of New South Wales.' (University of New South Wales Press Ltd: Sydney, Australia)
Hafliger E, Basle B, Lucerne J (1975) 'Ciba-Geigy weed tables: a synoptic presentation of the flora accompanying agricultural crops (JR Geigy: Basle)
Whibley DJ, Christensen TJ (1991) 'Garden weeds identification and control.' (Kangaroo Press: Sydney)
Wolff MA (1999) 'Winning the war on weeds: The essential gardener's guide to weed identification and control.' (Inkata Press: Sydney)
State Noxious Weed Control Board (2003) www.nwcb.wa.gov
Virginia Tech Weed Identification Guide (2004) www.nwcb.wa.gov
Prepared by Kylie Pethybridge, 2005
Checked by Carole Campbell, 2005
Updated by Justin KY Chu, July 2005
Checked by Dr Peter Michael, July 2005