FWS Focus

Overview

Characteristics
Overview

Yreka phlox is a perennial, low-growing plant in the phlox family (Polemoniaceae) that produces bright rose-pink to white flowers which bloom from April to June. It grows from a woody base, and mature Yreka phlox plants grow approximately two to six inches high and have hairy leaves and stems.

In 1876, Edward L. Greene, a priest in Yreka, California, made the first documented collection of Yreka phlox.  Since then, Yreka phlox have only been identified in five locations, all in the vicinity of Yreka, and all characterized by a certain group of soils, called serpentine.  Given the limited distribution of Yreka phlox, risks to this species include loss of habitat, illegal collection, competition with non-native plants, herbicide use, grazing, and wildfire.

In 2018, the Service conducted a 5-year status review of Yreka phlox, based on the best available scientific information. We concluded that Yreka phlox remains an endangered species. Currently, there is no habitat conservation plan, safe harbor agreement, or candidate conservation agreement for this species.

Long-term survival of Yreka phlox is dependent upon protecting and securing known occurrences of this species. 

This 5-year review summarizes the significant progress that has been made to understand, recover, and conserve Yreka phlox.

Links for More Information

National U.S. Fish and Wildlife Service Yreka Phlox Species Profile

Federal Register Notices & Documents

Survey Protocols: Guidelines for Reporting and Conducting Botanical Inventories and General Rare Plant Survey Guidelines

Yreka Fish and Wildlife Office Yreka Phlox Monitoring Project

 Maps

Scientific Name

Phlox hirsuta
Common Name
Yreka phlox
FWS Category
Flowering Plants
Kingdom

Location in Taxonomic Tree

Genus
Species

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

Yreka phlox is only found within the vicinity of Yreka, CA, growing at elevations ranging from 2,800 to 4,400 feet.  Yreka phlox grows only on serpentine soils, which contain high concentrations of magnesium and iron.  Serpentine soils are identified by red colored rocks due to high levels of iron or by green rocks due the high levels of magnesium.  These soils do not allow for the growth of many other plant species due high levels of magnesium and nickel and low calcium, nitrogen, phosphorous, and potassium levels.

Mountain

A landmass that projects conspicuously above its surroundings and is higher than a hill.

Rural

Environments influenced by humans in a less substantial way than cities. This can include agriculture, silvaculture, aquaculture, etc.

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

Yreka phlox is a perennial flowering plant, meaning it can grow for more than one season. It is commonly found at elevations of 2,800 to 4,400 feet.  Plants reach a height of up to 6 inches with stems and leaves that are covered in fine hairs.  Flowers are bright pink and measure 0.5 to 0.6 inches across.  The petals of Yreka phlox are rounded, not notched and fade in color as they age.

Color & Pattern

Yreka phlox produces bright rose-pink to white flowers which bloom from April to June. It grows from a woody base, and mature Yreka phlox plants grow approximately two to six inches high and have hairy leaves and stems.

Characteristic category

Similar Species

Characteristics
Similar Species

Showy Phlox (Phlox speciosa)

Showy phlox grow adjacent to and resemble Yreka phlox in overall plant shape and flower color.  Unlike Yreka phlox, showy phlox have notched petals.  Showy phlox occurs on both serpentine and non-serpentine soils.

Spreading Phlox (Phlox diffusa)Spreading phlox generally occurs at higher elevations than Yreka phlox. The overall plant shape is lower and denser than Yreka phlox. Flower color is commonly white, but can vary from deep pink to blue. While the stems and leaves of spreading phlox are hairy, they are not as hairy as Yreka phlox. Petals of spreading phlox are not notched.

Cold-desert Phlox (Phlox stansburyi)

Cold-desert phlox resembles the plant form and flower color of Yreka phlox, though it is not as compact nor as hairy as Yreka phlox.  Geographically, cold-desert phlox is most common east of the Sierra-Cascade crest in California.  Petals of cold-desert phlox are not notched.

Northern Phlox (Phlox adsurgens)

Northern phlox generally occurs at higher elevations than Yreka phlox. Unlike Yreka phlox, northern phlox are not hairy, leaves are broad, and flowers occur on long stalks. Petals of northern phlox are not notched.

Geography

Characteristics
Range

The known distribution of Yreka phlox covers a combined area of approximately 700 acres within Siskiyou County, California.  The number of plants at each location range from 200 to 10,000. 

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Timeline

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