Tonestus peirsonii

Tonestus peirsonii (syn. Lorandersonia peirsonii) is a species of flowering plant in the aster family known by the common names Peirson’s serpentweed and Peirson’s tonestus. The plant is endemic to California, where it is known only from the Eastern High Sierra Nevada, and the White Mountains across Owens Valley to the east, both within Inyo National Forest. It grows in mountain habitat in subalpine and alpine climates, such as talus. Tonestus peirsonii is a perennial herb producing a branching stem from a caudex and taproot unit, reaching up to about 20 centimeters tall and taking a clumpy form. The leaves are up to 8 centimeters long and are variable in shape, with toothed edges. The inflorescence is usually a single flower head, or a cluster of up to four heads, each up to 2 centimeters wide with green, rough-haired phyllaries. The head bears at least 16 bright yellow ray florets around a center containing many tubular disc florets. Blooming occurs in July and August.