Setaria sphacelata
African bristle grass
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Family: Poaceae · Type: Grass · Not Native
Setaria sphacelata (African bristle grass) is a non-native California grass in the Poaceae family, recognized by exceptional height and inflorescence length diagnostic.
African bristle grass is a naturalized perennial herb found in California's Great Valley and Carrizo Plain bioregions on ditch banks at elevations below 300 meters. Flowering from July to October, this grass produces pale inflorescences with distinctive bristles 9 to 40 centimeters long. Growing in tufted or clustered form with stems 60 to 300 centimeters tall, it has broad leaf blades 10 to 50 centimeters long and 3 to 15 millimeters wide. Its leaves have smooth surfaces with glabrous sheaths and small ligules approximately 1 to 2 millimeters long. The spikelets are tiny, measuring about 2 to 3 millimeters long with acute-tipped glumes and multiple delicate bristles.
Identification and appearance
Key characters: 4 sympatric species; exceptional height and inflorescence length diagnostic
Habitat and range
Habitat: Ditch banks
Elevation: < 300 m
Outside California: southeastern United States, native to Africa
Bloom period
Setaria sphacelata blooms Jul-Oct.
How to tell it apart
vs Cenchrus: Setaria bristles stay attached to the axis after the spikelet falls; Cenchrus bristles fuse into a spiny bur that drops with the seed.; vs Pennisetum: Setaria bristles are free and persistent below each spikelet; Pennisetum bristles form a deciduous involucre that falls as a unit with the spikelet.; vs Alopecurus: Setaria has stiff bare bristles subtending naked spikelets; Alopecurus has no bristles and its soft spikelets bear a bent awn from the lemma back.; vs Polypogon: Setaria's bristles are separate sterile branchlets left behind on the axis; in Polypogon the bristly look comes from awns on the glumes and the whole spikelet sheds.; vs Phleum: Setaria's cylindric head has projecting bristles between the spikelets; Phleum's dense spike is bristle-free with stiff, short-awned, keeled glumes.
Frequently asked questions
Is Setaria sphacelata native to California?
No. Setaria sphacelata is not native to California (recorded as not native).
When does Setaria sphacelata bloom?
Setaria sphacelata blooms Jul-Oct.
What plant family does Setaria sphacelata belong to?
Setaria sphacelata is in the Poaceae family, genus Setaria.
What habitat does Setaria sphacelata grow in?
Setaria sphacelata grows in Ditch banks.
Related species
Other California species in the same genus, family, or bioregion.
- Setaria verticillata — Hooked bristle grass
- Setaria viridis — Green bristle grass
- Setaria adhaerens — Bur bristle grass
- Setaria faberi — Chinese foxtail
- Setaria parviflora — Knotroot bristle grass
- Setaria pumila subsp. pumila — Yellow bristle grass
- Sorghum bicolor — Sorghum
- Sorghum halepense — Johnson grass
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.