Achnatherum richardsonii (Link) Barkworth
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TAXONOMY
 
Family: Poaceae
Genus: Achnatherum
 
Species Synonyms: Stipa richardsonii Link
Common Names: Richardson’s needlegrass
 
DISTRIBUTION
 
Canada: southern Yukon – British Columbia – Alberta – Saskatchewan – Manitoba
Saskatchewan: southern and central Saskatchewan; Cypress Hills – southern Prince Albert National Park – Bredenbury
Ecoregion: Cypress Upland, Moist Mixed Grassland, Aspen Parkland, Boreal Transition, Mid-Boreal Upland
 
HABITAT
 
Saskatchewan: upland prairie bordering woods or shrublands
Associated Species: alumroot, death camas, golden bean, prairie smoke, shortbristle needle and thread grass, slender wheatgrass
 
RARITY STATUS
 
Provincial Status According
to Harms (2003):
Vulnerable
Nature Conservancy Status:
G5 S2
Saskatchewan Species at
Risk Status:
None
COSEWIC Status:
None
 
Richardson’s needlegrass is vulnerable because it is rare or uncommon in Saskatchewan and most local populations are small. No immediate threats are known but are possible in the future.
 
SPECIES DESCRIPTION
 
Height: 50 – 80 cm
Roots: fibrous
Stems: perennial, tufted, erect
Leaves: mostly basal, blades 1 – 3 mm wide, rough, indistinctly veined, margin rolled; sheaths flattened, smooth or rough; ligules 1 mm long or less
Inflorescences: branched, 10 – 20 cm, open, branches slender, spreading or drooping
Spikelets: large, 1-flowered, separating above the glumes
Florets: glumes 8 – 10 mm long, about equal; hardened thickening at base of lemma bearded, sharp-pointed; lemmas 5 mm long, hardened, rolled longitudinally, brown at maturity; lemma awn 2 – 3 cm, twice-bent; palea enclosed in lemma
 Fruits: caryopsis with persistent awn
 
ACHNATHERUM KEY FOR SPECIES IN SASKATCHEWAN
 
1 Florets plump, hardened thickening at base of lemma oblique; lemma awn weak and deciduous
A. hymenoides
1 Florets slender, hardened thickening at base of lemma prolonged; lemma awn twice bent and persistent
2
   
2 Inflorescence open, branches spreading or drooping
A. richardsonii
2 Inflorescence narrow, branches ascending to erect
3
   
3 Awns at most 3.5 cm long; hardened thickening at base of lemma blunt, hairy except at tip
A. nelsonii ssp. dorei
3 Awns at most 0.6 cm long; hardened thickening at base of lemma sharp, hairless
A. nelsonii ssp. nelsonii