Species: Shinnersoseris rostrata (Gray) S. Tomb

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Shinnersoseris rostrata (Gray) S. Tomb

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TAXONOMY

Family:

Asteraceae or Compositae

Genus:

Shinnersoseris

Species Synonyms:

Lygodesmia rostrata (Gray) Gray

Common Names:

beaked annual skeletonweed
beaked skeletonweed

DISTRIBUTION

Canada:

southern Alberta – southwestern Saskatchewan, southwestern Manitoba

Saskatchewan:

southwestern Saskatchewan; Elbow – Mortlach – Empress

Ecoregion:

Cypress Upland, Mixed Grassland

HABITAT

Saskatchewan:

dry, sandy soil in semi-active to stabilized sand dunes

Associated species:

Canada wild rye, dune scurf pea, field sagewort, hairy false goldenaster, narrowleaf willow, prairie sandreed, prairie sunflower, sand dropseed, Schweinitz’s sedge, smooth goosefoot, veiny dock

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G5 S2

Saskatchewan Species at
Risk Status:

Vulnerable

COSEWIC Status:

None

Beaked annual skeletonweed is threatened because it is restricted to sand dune regions of the province. Most local populations are small. This species is easily mistaken for Lygodesmia juncea and may be overlooked.

SPECIES DESCRIPTION

Height:

20 – 100 cm

Roots:

taproot long, slender

Stems:

solitary, branches ascending, branching pattern appearing opposite from top, latex white, hairless

Leaves:

alternate, some appearing subopposite, 5 – 20 cm long, 1 – 2 mm wide, linear, hairless

Inflorescence:

heads with ray flowers only, few to several, 1 – 2.5 cm high, to 0.5 cm wide; bracts 7 – 9 in several series, 1 – 2 cm long, 1 – 2 mm wide, innermost series long and slender, green

Flowers:

ray flowers 7 – 9, purple or pink; pappus capillary bristles, simple, white to yellowish

Fruits:

achenes 8 – 10 mm long

SHINNERSOSERIS FROM MORPHOLICALLY SIMILAR SPECIES IN SASKATCHEWAN

1 Lower leaves toothed or divided; pappus feathery	Stephanomeria
1 Lower leaves entire; pappus simple	2

2 Perennial; branching pattern appearing irregular from the top; leaves reduced, usually less than 5 cm and scale-like; latex yellowish-green; bracts usually 5; pappus brown	Lygodesmia juncea
2 Annual; branching pattern appearing opposite from the top; leaves 5 – 20 cm long; latex white; bracts usually 7 – 9; pappus white	Shinnersoseris rostrata