Federal and State Listed Species of Texas:
Texas trailing phlox

Distribution

Current

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Distribution map of Texas trailing phlox (Phlox nivalis ssp. texensis ).

Scientific Name
Phlox nivalis ssp. texensis
Other Scientific Names
Phlox texensis, Phlox nivalis var. texensis
Other Common Names
Texan phlox
Status
Federally and State Endangered
Global Rank
G4T2
State Rank
S2

Global Location

Texas trailing phlox is only known from the Longleaf Pine region of East Texas in Hardin, Polk, and Tyler counties.

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Description

As its name indicates, Texas trailing phlox has stems that spread horizontally, then vertically, to form a small shrub 10-30 cm tall. Leaves persist on the woody stems year-round and are more abundant on horizontal stems. Non-flowering stems have grooved, needle-like leaves, and flowering stems have narrowly teardrop shaped leaves. All leaves are spine-tipped, edged with hairs, and 2.5-30 mm long. Flowers usually cluster in small groups of three to six. Flower petals are united into a tube, which flares into five-lobes, each with a single notch. Blooms can vary from pink to bluish to purple to white with a red to purple center. Flowers have a staff-like female structure, which extends 3-4 mm centrally from the flower’s base, but is hidden within the 11-17 mm long floral tube. Fruits are three-chambered, each chamber housing a single seed with an almost imperceptibly wrinkled surface.

Flower petals of Texas trailing phlox each have a single notch. Blooms can be pink with a darker center.

Credit: Sue Wilder - U.S. Fish and Wildlife Service

Texas trailing phlox has flower petals which form a tube that flares into five lobes, and has leaves that persist year-round.

Credit: Sonnia Hill

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Similar Species

The combination of its trailing nature, woody stems, and needle-like leaves distinguish Texas trailing phlox from all other phlox in the state. However, when spreading pygmyleaf (Loeflingia squarrosa ssp. squarrosa) has no flowers, it can look like Texas trailing phlox. But spreading pygmyleaf is somewhat fleshy, typically shorter (1-12 cm tall), and has shorter (0.4-5.5 mm) leaves, which fuse together in clumps at their bases.

Compared to Texas trailing phlox, spreading pygmyleaf is somewhat fleshy, typically shorter, and has smaller leaves, which fuse together in clumps at their bases.

Credit: Tony Valois - National Park Service

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Floral Characters

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Leaf Characters

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Habitat

Texas trailing phlox occurs on deep, sandy soils overlaying clays in open, fire-maintained pine or hardwood-pine plant communities.

Habitat of Texas trailing phlox.

Credit: The Nature Conservancy

Life Cycle Events

Flowering occurs from March to May.

Survey Season

Although Texas trailing phlox can be found year-round, it is most visible while in bloom from March to May.

Comments

Historically, Texas trailing phlox occurred in longleaf pine communities. However, longleaf pine communities have been replaced with the faster growing loblolly and slash pine in plantations. The original range of longleaf pine has been greatly reduced from its initial extent. Fire has also been suppressed for over 100 years in East Texas. Studies have shown that Texas trailing phlox is fire tolerant and prefers a 25%-50% canopy cover (Warnock 1996). It is unclear if loblolly and slash pines (opposed to longleaf pines) negatively affect Texas trailing phlox. However, site preparation for plantations and increased canopy cover impacts phlox populations.