Packera layneae
Encyclopedia
Packera layneae, known by the common name Layne's ragwort, is a rare species of flowering plant in the aster family
. It is endemic to California
, where it is known only from the western slopes of the northern Sierra Nevada foothills, such as the Pine Hill Ecological Reserve
.
; smaller leaves occur farther up the stems. The inflorescence
bears several flower heads
containing many yellow disc florets and several narrow yellow ray florets each up to 1.6 centimeters long.
and mountain woodlands, often on serpentine soil
s and weathered gabbro
. The plant faces several threats and was federally listed as a threatened species in 1996.
The plant grows in chaparral habitat that is dependent on wildfire
; fire suppression efforts alter growth and maintenance of plants in this ecosystem
. Other threats include development, mining
, off-road vehicle
use, grazing
, and the increasing presence of invasive plants
.
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...
. 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 western slopes of the northern Sierra Nevada foothills, such as the Pine Hill Ecological Reserve
Pine Hill Ecological Reserve
Pine Hill Ecological Reserve is a nature reserve of located due east of Folsom Lake, in El Dorado County, California. The reserve was established in 1979, and is managed by the California Department of Fish and Game....
.
Description
Packera layneae is a perennial herb producing an erect stem or a small cluster of stems up to 70 centimeters tall. The thick leaves have wide lance-shaped blades a few centimeters long which are borne on long petiolesPetiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
; smaller leaves occur farther up the stems. 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...
bears several flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
containing many yellow disc florets and several narrow yellow ray florets each up to 1.6 centimeters long.
Habitat
Packera layneae grows in chaparralChaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
and mountain woodlands, often on serpentine soil
Serpentine soil
A serpentine soil is derived from ultramafic rocks, in particular serpentinite, a rock formed by the hydration and metamorphic transformation of ultramafic rock from the Earth's mantle....
s and weathered gabbro
Gabbro
Gabbro refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
. The plant faces several threats and was federally listed as a threatened species in 1996.
The plant grows in chaparral habitat that is dependent on wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
; fire suppression efforts alter growth and maintenance of plants in this ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
. Other threats include development, mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
, off-road vehicle
Off-road vehicle
An off-road vehicle is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with deep, open treads, a flexible suspension, or even caterpillar tracks...
use, grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
, and the increasing presence of invasive plants
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
.