while brooks island has a variety of plant communities, the most common are coastal grassland and northern coastal scrub. it has been described as a "showcase for coastal grassland, which occurs on the island in a relatively undisturbed state", covering about of mostly flatter terrain. these grassland areas are relatively free of exotic mediterranean grasses and instead are dominated by needlegrasses (purple needlegrass ("nassella pulchra") and other"nassella" spp.), ryegrasses ("lolium" spp.) and fescues ("festuca" spp.). among the grasses are native wildflowers such as blue dicks ("dichelostemma capitatum"), soap plant ("chlorogalum parviflorum") and checker mallow ("sidalcea malviflora").