Agrostis hallii
Hall's bent grass, Hall's Bent Grass
(c) Jon Sullivan, some rights reserved (CC BY) · licence
Family: Poaceae · Type: Grass · Native
Agrostis hallii (Hall's bent grass) is a native California grass in the Poaceae family, recognized by prominent callus hairs, awnless lemmas, and long rhizomes.
Hall's bent grass is a California native perennial found in western Northwest California, central Coast, San Francisco Bay Area, northern southern California, and Western Transverse Ranges in open oak woodland and conifer forest at elevations below 1,800 meters. Flowering from May to July, this grass produces delicate, pale inflorescences 7 to 22 centimeters long in lanceolate to narrowly ovate clusters. Growing with slender stems 17 to 100 centimeters tall and spreading rhizomes up to 50 centimeters long, it forms dense grass clumps. Its leaf blades are flat, 7 to 20 centimeters long and 2 to 5 millimeters wide, with distinctive ligules 4 to 7 millimeters long. The plant's compact spikelets feature glumes 2.5 to 4 millimeters long with short callus hairs and minute pale anthers.
Identification and appearance
Key characters: 18 sympatric species; key features are prominent callus hairs, awnless lemmas, and long rhizomes
Habitat and range
Habitat: Open oak woodland, conifer forest
Elevation: < 1800 m
California counties: Humboldt, Alameda, Contra Costa, Del Norte, Marin, Mendocino, San Francisco, San Mateo, Siskiyou, Sonoma, Napa, Santa Cruz, Santa Clara, Santa Barbara, San Luis Obispo, Monterey, Lake, Trinity, Mariposa, Nevada, Ventura, Solano
Outside California: Oregon
Bloom period
Agrostis hallii blooms May-Jul.
How to tell it apart
vs Oloptum: Oloptum has prominent bent awns; Agrostis awns are tiny or absent.; vs Holcus: Holcus has velvety-hairy spikelets; Agrostis spikelets are smooth and glossy.; vs Polypogon: Polypogon has dense bristly panicles; Agrostis panicles are airy and delicate.; vs Poa: Poa has boat-shaped lemmas with 5 veins; Agrostis lemmas are rounded with faint veins.; vs Festuca: Festuca has multiple flowers per spikelet; Agrostis has single-flowered spikelets.
Frequently asked questions
Is Agrostis hallii native to California?
Yes. Agrostis hallii is native to California (recorded as native).
When does Agrostis hallii bloom?
Agrostis hallii blooms May-Jul.
Where in California does Agrostis hallii grow?
Agrostis hallii occurs in Humboldt, Alameda, Contra Costa, Del Norte, Marin, Mendocino, San Francisco, San Mateo and other counties, at elevations of < 1800 m.
What plant family does Agrostis hallii belong to?
Agrostis hallii is in the Poaceae family, genus Agrostis.
What habitat does Agrostis hallii grow in?
Agrostis hallii grows in Open oak woodland, conifer forest.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · 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.