Pseudotrillium
Pseudotrillium is a monotypic genus of flowering plants in the family Melanthiaceae containing the single species Pseudotrillium rivale. The genus was proposed in 2002 on the basis of morphology and molecular evidence that suggest the plant should no longer be included in genus Trillium.
Pseudotrillium rivale, known by the common name brook wakerobin, is endemic to the Siskiyou Mountains of southern Oregon and northern California, usually on soils of ultramafic origin, such as serpentine. The Latin specific epithet rivale means “growing by streams”, with reference to a preferred habitat.
Pseudotrillium rivale is a rhizomatous herbaceous perennial growing up to in height. The three bracts have generally lance-shaped blades up to long borne on petioles in length. The blades are glossy blue-green with silvery venations. Atop the whorl of bracts, on a pedicel high, is a single nodding non-fragrant flower with green sepals and pink-blushed white petals up to long by wide.
The plant flowers April to June. After flowering, the entire plant may enlarge and become more robust and turgid with very glossy leaves. By mid-July, the entire plant withers and goes dormant.
Under its former name, Trillium rivale, this plant has gained the Royal Horticultural Society's Award of Garden Merit. Hardy down to, it requires a sheltered position in partial or full shade.
