Rough cat's ear is a non-native herbaceous perennial that can reach about 3' in height, but is often shorter.  Both of the Hypochaeris species in California have erect stems with milky sap, but as the name indicates, while glabra is glabrous, radicata is rough-
hairy, something well-illustrated in the last picture below.  H. glabra is also an annual with a slender taproot, whereas H. radicata has a fleshy taproot.  This cat's ear has leaves that are 2" to 5-1/2" long, ± spatulate-shaped, and pinnately cleft into shallow lobes or teeth, and like glabra are in a basal rosette.  The flowering heads are ligulate and yellow in color, and the ligules are 5-toothed. Another difference between the two species is that H. glabra has short inconspicuous ligules while those in H. radicata are longer and much more conspicuous.  The achene body is brownish with a slender beak and feathery pappus.  Although the Jepson Manual says it is abundant, the only place I have ever seen it is where I took these photos, in my friend Tom Chester's front yard in Fallbrook.  It is a weed of lawns and disturbed places mostly nearer the coast, blooming from May to November, and is naturalized from Europe.

Click here for Latin name derivations: 1) Hypochaeris  2) radicata.
Pronunciation: hy-po-KEER-is rad-i-KAY-ta.
Click here for Botanical Term Meanings.