As part of the California Floristic Province, the Santa Ana Mountains host a diverse array of plant species within distinctive natural (plant) communities, including coastal sage scrub, chaparral, riparian woodland, southern oak woodland, rocky outcrop, vernal pool, valley grassland, and closed-cone montane coniferous forest. One of the southernmost stands of madrones can be found in Trabuco Canyon. Groves of knobcone pine can be found around Pleasants Peak. Big-cone Douglas fir and Coulter pine can be found at the higher elevations. Rare flowers like the intermediate Mariposa lily, heart-leaved pitcher sage (associated with the Tecate cypress), and chocolate lily are difficult to find, but breathtaking to observe. Fragrant sages, broadleaf evergreen shrubs and trees, perennial bunchgrasses, strange succulents (Dudleya species), and fire-following flowers adorn the rugged terrain. Numerous ferns, including large sword ferns, are found under trees and near streams, especially at higher elevations.