Tonestus peirsonii
Encyclopedia
Tonestus peirsonii is a species of flowering plant in the aster family
known by the common name Peirson's serpentweed. It is endemic to California
, where it is known only from the High Sierra Nevada and adjacent mountain ranges to the east. It grows in mountain habitat in subalpine
and alpine climate
s, such as talus
. It 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.
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
known by the common name Peirson's serpentweed. It is endemic to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, where it is known only from the High Sierra Nevada and adjacent mountain ranges to the east. It grows in mountain habitat in subalpine
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...
and alpine climate
Alpine climate
Alpine climate is the average weather for a region above the tree line. This climate is also referred to as mountain climate or highland climate....
s, such as talus
Scree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...
. It is a perennial herb producing a branching stem from a caudex
Caudex
A caudex is a form of stem morphology appearing as a thickened, short, perennial stem that is either underground or near ground level . It may be swollen for the purpose of water storage, especially in xerophytes...
and taproot
Taproot
A taproot is an enlarged, somewhat straight to tapering plant root that grows vertically downward. It forms a center from which other roots sprout laterally.Plants with taproots are difficult to transplant...
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
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is usually a single flower head
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
, or a cluster of up to four heads, each up to 2 centimeters wide with green, rough-haired phyllaries
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
. The head bears at least 16 bright yellow ray florets around a center containing many tubular disc florets. Blooming occurs in July and August.