Crepis occidentalis ssp. costata (Gray) Babcock & Stebbings
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TAXONOMY
 
Family: Asteraceae or Compositae
Genus: Crepis
 
Species Synonyms: Crepis occidentalis var. costata Gary
Psilochenia occidentalis ssp. costata (Gray) W.A. Weber
Common Names: western hawksbeard
largeflower hawksbeard
 
DISTRIBUTION
 
Canada: southern British Columbia – southwestern Saskatchewan
Saskatchewan: southwestern Saskatchewan; Cypress Hills, Frenchman River, Saskatchewan River
Ecoregion: Cypress Uplands, Mixed Grassland
 
HABITAT
 
Saskatchewan: coarse-textured or gravelly soils on sparsely to well-vegetated slopes
Associated species: Astragalus pectinatus, Gaillardia aristata, Muhlenbergia cuspidata, Stephanomeria runcinata, Thermopsis rhombifolia
 
RARITY STATUS
 
Provincial Status According
to Harms (2003):
Threatened
Nature Conservancy Status:
G5 N2 S2
Saskatchewan Species at
Risk Status:
None
COSEWIC Status:
None
 
Crepis occidentalis ssp. costata is threatened because of rarity in Saskatchewan. It is somewhat regionally restricted within the province and almost always locally sparse. The most imminent threat to this species is habitat loss.
 
SPECIES DESCRIPTION
 
Height: 20 – 40 cm
Roots: taproot
Stems: caudex with overlapping leaf bases; stems 1 – 3 from caudex, branched near top, gray tomentulose, glandular upwards
Leaves: basal and cauline; basal leaves several in rosette, petiole winged, leaves 10 – 30 cm long, runcinate toothed to pinnatifed, grey tomentulose; cauline leaves few, sessile, not auriculate, reduced upwards, uppermost bract-like, runcinate toothed to pinnatifed to linear, gray tomentulose, glandular-hairy upwards
Inflorescence: heads 2 – 20 in corymbiform cluster, to 1.5 cm long, 0.5 – 1 cm broad, 12 – 20-flowered; ligulate; phyllaries in 2 series, the outer less than half as long as the inner, straw-coloured with dark brown midvein, hairs gland-tipped; receptacle naked
Flowers: ligulate florets to 2 cm long, yellow, perfect; pappus white, capillary bristles
Fruits: achene 6 – 10 mm long, fusiform, 10 – 20-ribbed, beakless, brownish
 
CREPIS KEY FOR SPECIES FOUND IN SASKATCHEWAN
 
1 Annual; cauline leaves auriculate
C. tectorum
1 Perennial; cauline leaves if present, not auriculate
2
   
2 Stems and cauline leaves glabrous (or at most weakly hispid); leaves entire or dentate
3
2 Stems tomentose or puberulent; leaves pinnatifed
4
   
3 Involucral bracts not hairy or glandular
C. runcinata ssp. glauca
3 Leaves glandular along midrib
C. runcinata ssp. hispidulosa
 
4 Leaf segments linear to narrowly lanceolate, usually entire; achenes greenish
C. atribarba
4 Leaf segments lanceolate, usually toothed; achenes greenish or brownish
5
 
5 Plants usually < 35 cm tall; involucre glandular-hairy
C. occidentalis ssp. costata
5 Plants usually > 35 cm tall; involucre not glandular-hairy
C. intermedia