Plant Image
Seedhead
- Patrick Alexander @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)


Yavapai County Native & Naturalized Plants

Achnatherum robustum - sleepygrass

Synonyms: Stipa robust
Plant Form: Grass

Family: Poaceae


   
 
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Plant - summer
Patrick Alexander @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)
Seedhead
Patrick Alexander @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)
Spikelets
Patrick Alexander @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)
Hairy collar and ligule
Patrick Alexander @http://swbiodiversity.org, Usage Rights: Creative Commons Attribution-ShareAlike (CC BY-SA)
  Grass Description -   Glossary of Grass Terminology


Origin: Native    Season: Warm
Habitat Description: Dry plains and hills, open woods and forest clearings, and along roadsides.
Plant Communities:Interior Chaparral, Semidesert Grasslands, Pinyon Juniper Woodland, Montane Conifer Forest, Disturbed Areas
Elevation: 4000 - 8000 feet

Similar Species: A. nelsonii
General Description

Desc: Stems erect or ascending (curving upward) and growing in dense tufts or clusters, without rhizomes. Leaves mostly below the middle of the stem in 2 vertical ranks on opposite sides of the stem.
Identification Notes: Sheath collars are very hairy. The lower nodes of the seedhead are also hairy. Plant is robust, often more than 3 feet tall. Glumes are firm.
Grass Type: Perennial bunchgrass  Rhizomes: N  Stolons: N
Large Dense Clump (> 2 feet): N  Bushy (highly branched): N
Height with Seedheads: Greater than 36 inches
Seedhead Structure: Branched - contracted  Seedhead Droops: N
Flowering Period: Jun - Sep
Flower Characteristics

Number of Flowers per Spikelet: One-flowered  Spikelets One-sided: N
Awns: Greater than 1 inch   Three Awns: N  Awns Bent: Y
Flower and Seedhead Notes: Inflorescence a tight, contracted panicle, with 1 spike or cluster per stem. Awns 3/4 to 1-1/2 inches long or longer, twisted like a corkscrew, and twice geniculate (bent twice).
Vegetative Charcteristics

Blade Hairy: N    Blade with White Margins: N    Blade Cross section: Flat or involute
Blade Notes: Linear leaf blades 1/8 to 3/8 inch wide and hairless. Leaf blades mostly flat with the margins rolled inward. Bottom surface smooth, top surface roughly ribbed.
Sheath Hairy: N    Tuft of Hairs at top of Sheath or Collar: Y    Ligules: Membranous
Auricles (Ear-like lobes at collar area: N

Forage Value: Contains diacetone alcohol which can be poisonous to livestock, hence the common name sleepygrass.


  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 8.0  
http://cales.arizona.edu/yavapaiplants/SpeciesDetailGrass.php  
Last Updated: Dec 13, 2022
Content Questions/Comments: Email Matt Halldorson  
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