giant wakerobin

Trillium chloropetalum is a perennial, clump-forming herbaceous plant with a thick underground rhizome. Like all trilliums, it has a whorl of three bracts (leaves) and a single trimerous flower with 3 sepals, 3 petals, two whorls of 3 stamens each, and 3 carpels fused into a single ovary with 3 stigmas. Since its flower has no stalk, T. chloropetalum belongs to subgenus Sessilia, the sessile-flowered trilliums. It is one of the largest of all Trillium species, with a scape (stem) from 20 to 70 cm (7.9 to 27.6 in) long. The bracts are broadly ovate, 7 to 21 cm (2.8 to 8.3 in) long and 7 to 18 cm (2.8 to 7.1 in) wide, usually with brownish mottling but sometimes unmottled. Petal color is highly variable, typically ranging from pale greenish yellow to greenish bronze (or purplish green) to dark purple. A variety that lacks yellow pigments has petal colors ranging from white to reddish-purple. The flower petals enclose purple stamens, 15 to 30 mm (0.59 to 1.18 in) long, and a purple ovary. Flowering occurs from late February to early April. In the San Francisco Bay Area, a white-petaled form of T. chloropetalum is often confused with T. albidum, which also has white petals. The former is distinguished by the purple pigment in its anther connective tissue, a character lacking in T. albidum.

Trillium chloropetalum is endemic to California. Some authorities claim the species ranges across ten California counties, from Monterey County on the central California coast to Lake County in the north central part of the state:

Alameda, Contra Costa, Lake, Marin, Monterey, Napa, San Mateo, Santa Clara, Santa Cruz, Sonoma Other authorities claim that T. chloropetalum has a broader range that extends northward to Siskiyou County or southward to Santa Barbara County. T. chloropetalum is found at the edges of redwood forests and chaparral, usually on moist slopes, canyon banks, and alluvial soils.

The variety Trillium chloropetalum var. giganteum, with its deep maroon flower petals, gained the Award of Garden Merit (AGM) from the Royal Horticultural Society in 1993.