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Yavapai County Native & Naturalized Plants

Setaria macrostachya - large-spike bristlegrass

Synonyms: Chaetochloa gibbosa, C. macrostachya, C.amaeraphis setosa var. macrostachya, Panicum macrostachyum and more, See SEINET.

Plant Form:Grass

Family: Poaceae

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  Grass Description -   Glossary of Grass Terminology

Origin: Native    Season: Cool and Warm
Habitat Description: Found on dry flats and in washes, often in partial shade of trees and shrubs.
Plant Communities: Interior Chaparral, Pinyon Juniper Woodland, Montane Conifer Forest
Elevation: 3500 - 7000 feet

General Description

Desc: Robust, somewhat erect perennial with leaves 1/2 to 3/4 inch wide, columnar spike-like panicles 4 to 12 inches long; spikelets are very rounded on the back.
Identification notes: Densely tufted, exceeds 2 feet; stems somewhat bent, rough below nodes; dense spikelike seedheads; subspherical spikelets usually subtended by one 3/8 to 3/4 inch bristle, bristles rough to the touch on the upper surface, palea shorter than the lemma.
Grass Type: Perennial bunchgrass  Rhizomes: N  Stolons: N
Large Dense Clump (> 2 feet): Y  Bushy (highly branched): N
Height with Seedheads: Greater than 36 inches
Seedhead Structure: Branched - contracted  Seedhead Droops: N
Flowering Period: May - Oct

Flower Characteristics

Number of Flowers per Spikelet: Multi-flowered  Spikelets One-sided: N
Awns: Absent   Three Awns: N  Awns Bent: N

Flower and Seedhead Notes: Seedheads rarely branched distally, rough below the nodes and panicles. Spikelets 1/16 inch, not quite round, 2-flowered, pale green. Lower glumes 1/3 to 1/2 as long as the spikelets, upper glumes about 3/4 as long as the spikelets.

Vegetative Characteristics

Blade Hairy: N  Blade with White Margin: N  Blade Cross Section: Flat  
Blade Notes: Blades 6 to 8 inches long, 1/4 to 3/4 inch wide, flat, with rough upper surface.
Sheath Hairy: Y  Tuft of Hairs Top of Sheath or Collar: N  Ligules: Hairy
Auricles (Ear-like lobes at base of blades): N
Vegetative Notes: Sheaths keeled, free from hair except for a few white hairs at the throat. Ligules densely ciliate, 1/16 to 1/4 inch, with tuft of hair on either side.

Forage Value: Not available.

  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 8.0  
Last Updated: Feb 16, 2020  
Content Questions/Comments: Email Jeff Schalau  
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