Plant of the Week
Umpqua mariposa lily (Calochortus umpquaensis Fredricks
By Russell Holmes
Umpqua mariposa lily is in the Liliaceae (lily family) which contains 478 species in North America and approximately 4,200 species worldwide. Liliaceae is a diverse plant family that contains numerous important ornamentals, a number of important agricultural crops, and has been the source of valuable pharmacopoeia. The family has a near worldwide distribution but most species grow in tropical areas. Umpqua mariposa lily is a narrow endemic species restricted to the Klamath Mountains physiographic province of southwestern Oregon. Most of the populations occur within a single river drainage.
Umpqua mariposa lily is an erect perennial herb arising from an ovoid bulb. It produces a single leaf 20 to 30 cm (8 to 12 inches) long with short hairs along the parallel veins of the inner surface. The outer surface is hairless. The inflorescence is one to several flowered with one or more pairs of bracts. Flowers are erect with three petals and three sepals. Each petal is approximately 3.5 cm (1.4 inches) long, white to cream in color with a dark purple spot at the base. Dense purple hairs cover the lower portion of each petal. Increasingly sparse white hairs cover the upper half of the petal. The fruit is a nodding capsule 3 to 5.4 cm (1.2 to 2 inches) long.
Habitat ranges from open meadows to forested slopes on serpentine soils. Plants grow best in open meadows and along forest edges. Serpentine soils have high concentrations of heavy metals, such as nickel and cadmium and unusually low levels of nutrients essential for plant growth such as nitrogen, calcium, and potassium forming an inhospitable environment for many plant species. Associated species of Umpqua mariposa lily include Jeffrey pine (Pinus jeffreyi), incense cedar (Calocedrus decurrens), Douglas-fir (Pseudotsuga menziesii), Hooker’s silene (Silene hookeri ssp. hookeri), showy tarweed (Madia elegans var. densifolia), cismontane minuartia (Minuartia cismontane) and Roemer’s fescue (Festuca roemeri).
For More Information: PLANTS Profile - Calochortus umpquaensis, Umpqua mariposa lily