Polypogon interruptus
Ditch beard grass
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Family: Poaceae · Type: Grass · Native
Polypogon interruptus (Ditch beard grass) is a native California grass in the Poaceae family, recognized by native status and interrupted inflorescence.
Ditch beard grass is a California native perennial found in coastal, central, and southern California regions on streambanks at elevations below 1,300 meters. Flowering from May to August, this grass produces delicate purple-tinged flowers in lobed, interrupted inflorescences 1.5 to 18 centimeters long. Growing in clumped formations with stems 50 to 90 centimeters tall, it develops dense, spreading clusters. Its leaves have distinctive ligules 2 to 8 millimeters long, with narrow blades 0.5 to 19.5 centimeters in length and 3 to 6 millimeters wide. The grass has small, scabrous flower glumes with short awns that give it a soft, textured appearance.
Identification and appearance
Key characters: 5 sympatric species; native status and interrupted inflorescence are diagnostic
Habitat and range
Habitat: Common. Streambanks
Elevation: < 1300 m
Outside California: to south-central United States, native to South America
Bloom period
Polypogon interruptus blooms May-Aug.
How to tell it apart
vs Lagurus: Beard grass has loose fuzzy heads in wet areas; hare's tail has dense white-woolly oval heads in dry areas.; vs Cynosurus: Beard grass has soft fuzzy bristled heads; dogtail has hard one-sided spike-like heads.; vs Hordeum: Beard grass has soft fuzzy heads; barley has stiff, harsh-awned spike-like heads.; vs Setaria: Beard grass spikelets fall intact; foxtail bristles remain on stem after seeds fall.; vs Trifolium: Polypogon is a grass with fuzzy flower spikes; Trifolium is a legume with clover-leaf clusters.
Frequently asked questions
Is Polypogon interruptus native to California?
Yes. Polypogon interruptus is native to California (recorded as native).
When does Polypogon interruptus bloom?
Polypogon interruptus blooms May-Aug.
What plant family does Polypogon interruptus belong to?
Polypogon interruptus is in the Poaceae family, genus Polypogon.
What habitat does Polypogon interruptus grow in?
Polypogon interruptus grows in Common. Streambanks.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.