Encelia resinifera
Encyclopedia
Encelia resinifera is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

 in the family Asteraceae
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...

, native to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

Description

This species is a shrub ranging in height from 40 to 150 cm. The trunk, which becomes fissured with age, supports slender stems. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

, which range between 10 and 25 mm in length, are ovate or lanceolate and are usually pointed at the tips. The yellow flowerheads are borne singly, appearing between May and July (late fall to mid-summer) in their native range. These have 8-13 ray florets.

Taxonomy

E. resinifera was originally described as a variety of E. frutescens
Encelia frutescens
Encelia frutescens is a species of flowering plant in the daisy family known by the common names button brittlebush and bush encelia.-Distribution:...

 (E. frutescens var. resinosa) by M.E.Jones in 1913. In 1998 it was reclassified as a species in its own right by Curtis Clark.

Two subspecies have been identified, as follows:
  • E. resinifera subsp. resinifera - button brittlebush
  • E. resinifera subsp. tenuifolia C.Clark, which is found in the Grand Canyon
    Grand Canyon
    The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...

     area. This subspecies has both leaves and ray laminae with a length that is more than three times their width.

Distribution

The species is found at elevations between 1100 and 1700 metres in the states of Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

 and Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

 in soils derived from sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

.
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