About Streptanthus morrisonii F.W.Hoffm.
Streptanthus morrisonii F.W.Hoffm., commonly called Morrison's jewelflower, is an uncommon flowering plant species in the mustard family. It is endemic to California, found only in the North and Central Coast Ranges. It grows exclusively on serpentine soils in chaparral and forest habitats. This taxon is treated as a species complex that includes Streptanthus brachiatus, and is divided into four variable subspecies. As a general description, S. morrisonii is a biennial herb that produces a hairless, waxy stem reaching a maximum height between 1.2 and 1.5 meters, often branching at the tip. Its basal leaves have fleshy, lance-shaped blades 3 to 5 centimeters long, attached to petioles. The upper blade surface is gray-green, while the underside is purple or mottled with purple. Leaves located higher on the stem vary in shape and decrease in size toward the top of the plant. Flowers grow at intervals along the upper section of the stem. Each flower has an urn-shaped calyx made of keeled sepals, which range in color from yellow-green to purple. The petals that emerge from the tip of the calyx are whitish with purple-brown veining. The fruit is a flattened straight or slightly curved silique that can grow up to 8 centimeters long. This species is threatened by boron toxicity caused by steam released from nearby geothermal power plants.
