Phlox muscoides
Squarestem phlox, Squarestem Phlox
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Family: Polemoniaceae · Type: Perennial · Native
Conservation status: CNPS 2B.3
Phlox muscoides (Squarestem phlox) is a native California perennial in the Polemoniaceae family, recognized by tightly cushioned habit with 4-ranked overlapping leaves that hide stems.
Squarestem phlox is a rare (CNPS 2B.3) California native perennial found in the Loomis Peak area of the northern Sierra Nevada in open, rocky areas at elevations of 1,400 to 2,700 meters. Flowering from May to June, this plant produces white to lilac flowers with delicate petals nestled within its dense, tightly cushion-like form. Growing in compact clusters with stems completely hidden by overlapping leaves, it forms a low, intricate mat of vegetation typically 3 to 5 centimeters tall. Its leaves are densely covered in long, woolly hairs, arranged in a precise four-ranked pattern that completely obscures the underlying stem structure. Each flower emerges sessile within this compact cushion, with a hairy calyx approximately 5 millimeters long.
Identification and appearance
Key characters: 3 sympatric species; key features are tightly cushioned habit with 4-ranked overlapping leaves that hide stems
Habitat and range
Habitat: Open, rocky areas
Elevation: 1400-2700 m
Outside California: to Oregon, western Great Plains, Colorado
Bloom period
Phlox muscoides blooms May-Jun.
Conservation status
CNPS 2B.3
How to tell it apart
vs Linanthus: Phlox has opposite leaves; Linanthus has alternate leaves arranged singly along the stem.; vs Leptosiphon: Phlox leaves are completely undivided blades; Leptosiphon leaves are deeply cut into finger-like segments.; vs Pelargonium: Phlox has opposite, narrow unlobed leaves; Pelargonium has alternate, round lobed leaves with strong scent.; vs Catharanthus: Phlox is native with opposite leaves; Catharanthus (periwinkle) has glossy opposite leaves with white midvein.; vs Dianthus: Phlox has spreading 5-petaled flowers with tube; Dianthus has fringed or toothed petals emerging from tubular calyx.
Frequently asked questions
Is Phlox muscoides native to California?
Yes. Phlox muscoides is native to California (recorded as native).
When does Phlox muscoides bloom?
Phlox muscoides blooms May-Jun.
What plant family does Phlox muscoides belong to?
Phlox muscoides is in the Polemoniaceae family, genus Phlox.
Is Phlox muscoides rare or endangered?
Phlox muscoides carries California Rare Plant Rank 2B.3, state rank S3.
What habitat does Phlox muscoides grow in?
Phlox muscoides grows in Open, rocky areas.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
Last updated 2026-10-06
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.