The species is frequently confused with Monolopia lanceolata, with the two being very similar in appearance.

M. major appears to only occur where average annual precipitation is greater than about 11 inches per year (chaparral, blue oak woodland), whereas M. lanceolata can occur at average annual precipitation greater than 11 inches per year, but also at precipitation levels as low as 6 inches per year (San Joaquin Valley Desert; saltbrush scrub).

Monolopia major is an annual herb producing a slender, sometimes branching stem up to about 80 centimeters tall.

The inflorescences at the ends of stem branches bear small hemispheric flower heads with fused phyllaries.

The golden, yellow, or cream-colored ray florets are up to 2 centimeters long and have three-lobed tips.