Synonyms: Trillium angustipetalum, Trillium chloropetalum
Referred to as Trillium angustipetalum in "The Jepson Manual: Higher Plants of California", the giant purple wakerobin is an attractive perennial wildflower for the woodland garden. The stiff stems are erect to ascending and rise from 20-70 cm high. The trio of stem leaves arise from the same point at the apex of the stem and have sessile or very short petiolate bases. The blades are rounded to obtuse, and are sometimes mottled with light brown, dark green or gray splotches on the upper surface. Each blade measures from 9-25 cm long.
The single flower is sessile and rests direcly upon the leaves. The 3 sepals are oblong-lanceolate to linear-lanceolate in outline and measure from 3-6.5 cm long. The 3 petals are linear to oblong-lanceolate in shape and measure from 5-11 cm long. Both the petals and sepals are dark purple or maroon in color. The sepals are typically spreading while the petals are erect as shown in the photo above. The stamens measure 11-23 mm long. The flowers typically have a musty to fetid odor. I'm assuming this odor would attract flies and other similar insects as pollinators.
Within its natural range, the giant purple wakerobin may be foundin chaparral, woodlands of the foothills and on the forest floor beneath conifers in the mountains.
In the United States, giant purple wakerobin may be found west of the coast ranges from southern California north to southern Oregon
This species has been reported as naturalized in the western Columbia River Gorge, but I have yet to see the plant or know precisely of its location or whether it is native here or introduced.