Heterotheca monarchensis
Encyclopedia
Heterotheca monarchensis is a rare species of flowering plant in the aster family
known by the common name monarch goldenaster. It is endemic to Fresno County, California
, where it is known from only one location near Boyden Cave
in the Kings River Canyon
. It grows in the limestone
cliffs of this Sierra Nevada river canyon, along with a few other rare local endemics. The plant was discovered in July, 1995, and described to science as a new species in 1996.
This is a perennial herb anchored in the rocky substrate by a taproot
and producing one to many erect, spreading stems up to about 18 centimeters tall. The leaves have lance-shaped or oval blades which are densely hairy and bristly in texture, with some resin glands. They measure up to 2.5 centimeters long by a few millimeters in width and do not become much smaller toward the ends of the branches. The inflorescence
contains one to five flower heads
, each with up to 19 yellow ray florets measuring 1 to 1.5 centimeters in length. At the center are many hairy yellow disc florets.
There are approximately 500 individuals of this plant in existence. It is impacted by introduced plant species
, especially red brome
(Bromus madritensis ssp. rubens).
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 monarch goldenaster. It is endemic to Fresno County, California
Fresno County, California
Fresno County is a county located in the Central Valley of the U.S. state of California, south of Stockton and north of Bakersfield. As of the 2010 census, it is the tenth most populous county in California with a population of 930,450, and the sixth largest in size with an area of . The county...
, where it is known from only one location near Boyden Cave
Boyden Cave
Boyden Cave is karst cavern located in California's Giant Sequoia National Monument, along the Kings Canyon Scenic Byway, and just west of Kings Canyon National Park. Regular tours of the cave are given by a licensed guide company between April and November. It is a magnificent cavern with many...
in the Kings River Canyon
Kings River (California)
The Kings River is a major river of south-central California. About long, it drains an area of the high western Sierra Nevada and the Central Valley. A large alluvial fan has formed where the river's gradient decreases in the Central Valley so the river divides into distributaries...
. It grows in the limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
cliffs of this Sierra Nevada river canyon, along with a few other rare local endemics. The plant was discovered in July, 1995, and described to science as a new species in 1996.
This is a perennial herb anchored in the rocky substrate by a 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...
and producing one to many erect, spreading stems up to about 18 centimeters tall. The leaves have lance-shaped or oval blades which are densely hairy and bristly in texture, with some resin glands. They measure up to 2.5 centimeters long by a few millimeters in width and do not become much smaller toward the ends of the branches. 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...
contains one to five flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
, each with up to 19 yellow ray florets measuring 1 to 1.5 centimeters in length. At the center are many hairy yellow disc florets.
There are approximately 500 individuals of this plant in existence. It is impacted by introduced plant species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
, especially red brome
Bromus madritensis
Bromus madritensis is a species of brome grass known by the common name compact brome.It is native to Europe but it has been widely introduced elsewhere, such as North America, where it is found in many areas. It is now known nearly worldwide...
(Bromus madritensis ssp. rubens).