Species: Hieracium albiflorum Hook.

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Hieracium albiflorum Hook.

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TAXONOMY

Family:

Asteraceae or Compositae

Genus:

Hieracium

Species Synonyms:

Chlorocrepis albiflora (Hook.) W.A. Weber
Hieracium helleri Gandog.

Common Names:

white-flowered hawkweed

DISTRIBUTION

Canada:

northwestern Mackenzie District – British Columbia – southwestern Saskatchewan.

Saskatchewan:

southwestern Saskatchewan; Cypress Hills

Ecoregion:

Cypress Upland

HABITAT

Saskatchewan:

dry or gravelly soils in woods or grasslands

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G4G5 S1S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

White-flowered hawkweed is threatened because it is highly regionally restricted in the province. This species is locally abundant in the Cypress Hills.

SPECIES DESCRIPTION

Height:

30 – 80 cm tall

Roots:

roots fibrous; rhizomes

Stem:

hairless to sparingly hairy

Leaves:

basal and one the stem; basal leaves several, stalks short with rusty hairs, 4 – 15 cm long, 3 – 6 cm wide, broadly to narrowly spoon-shaped to oblong, sparsely hairy, more hairy on midvein, margin remotely toothed; stem leaves few, reduced upwards, almost bract-like near the top, alternate, sessile, sparsely rusty long-hairy especially at base

Inflorescence:

heads several in compound clusters, 0.5 – 0.8 mm broad, ray flowers only; bracts in 2 – 3 series, outer series half as long as inner, 6 – 10 mm high, dark green, inner series dry and membranous margined, hairless to sparsely hairy, glandular at base

Flowers:

ray flowers 12 – 30, white or creamy

Fruits:

achenes slender, ribbed; pappus or capillary bristles, to 3 mm long, off-white

*KEY TO HIERACIUM* IN SASKATCHEWAN**

1 Flowers white or creamy; star-shaped hairs absent	H. albiflorum
1 Flowers yellow or orange; usually with at least some star-shaped hairs	2

2 Roots long and slender, with offshoots; stem (scape) soft, long straight hairs, leafless or with one or two small leaves; flowers orange	H. aurantiacum
2 Roots short and stout, without offshoots; stem firm and leafy; flowers yellow	3

3 Leaves with rolled under, rough-hairy margins, linear to narrowly lance-shaped, upper narrowed or rounded at base, leaves 4 – 12 times longer than broad	H. umbellatum
3 Leaves flat, margins not rough hairy, lance-shaped to oval, upper squared to nearly heart-shaped at base, leaves 2 – 5 times longer than broad	H. canadense var. canadense