T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Hypochoeris radicata (Catsear)

Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
(Unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Cichorieae
Genus: Hypochoeris
Species: H. radicata
Binomial name: Hypochoeris radicata
Common name: Catsear, Flatweed, Cat's ear, False Dandelion, Common catsear, Deep-rooted Catsear, Rooted Catsear, Wet-the-Bed

Hypochoeris radicata is a perennial, low-lying edible herb often found in lawns, pastures, river-beds, road-sides and waste ground. The plant is native to Europe, but has also been introduced to New Zealand and is one of the most widely distributed weed.
The leaves, which may grow up to eight inches, are lobed and covered in fine hairs, forming a low-lying rosette around a central taproot. 
Stems are leafless and branched and can be up to 60cm tall. The stems carry bright yellow flower heads, and when mature these form seeds that are attached to windborne "parachutes". All parts of the plant emit a milky sap when broken. or cut. The fresh leaves seem also to be edible and can be added to salads. 

In the vegetative phase, Catsear can be differentiated from Dandelion and Hawksbeard because it has hairy leaves, unlike the other two. However, Hawkbit also has hairy leaves, so telling vegetative Catsear and Hawkbit plants apart are more tricky. Dandelion has more divided leaves with the tips of the lobes pointing towards the base of the leaf.
Catsear and Hawksbeard stems are branched whereas hawkbit and dandelion have unbranched flower stems.   

The conspicuous yellow flowers of the Catsear (Hypochaeris radicata) on a New Plymouth rural road.

A young rosette

Branched flower stems.

The seedhead.

The hairy leaves of Hypochoeris radicata

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/