Species: Packera plattensis (Nutt.) W.A. Weber & A. Löve

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Packera plattensis (Nutt.) W.A. Weber & A. Löve

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TAXONOMY

Family:

Asteraceae or Compositae

Genus:

Packera

Species Synonyms:

Senecio pseudotomentosus Mackenzie & Bush
Senecio plattensis Nutt.

Common Names:

prairie groundsel

DISTRIBUTION

Canada:

Mackenzie District – British Columbia – Ontario

Saskatchewan:

widespread; Lake Athabasca – Cypress Hills

Ecoregion:

Cypress Upland, Moist Mixed Grassland, Aspen Parkland, Boreal Transition, Mid-Boreal Lowland, Mid-Boreal Upland, Churchill River Upland, Tazin Lake Upland

HABITAT

Saskatchewan:

grasslands, sloughs, shores and open woods

Associated Species:

Agoseris sp., Crepis sp., Populus tremuloides

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G5 S3S4

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Packera plattensis is threatened; however this complex needs taxonomic revision. Most specimens of Packera plattensis in Saskatchewan have been re-identified as Packera paupercula and it is unclear where this species really exists. No threats are known or anticipated for Packera plattensis at the present time.

SPECIES DESCRIPTION

Roots:

fibrous; sometimes with stolons

Stems:

caudex short, ascending; stems solitary, rarely 2 – 3, lightly floccose tomentose or irregularly glabrate

Leaves:

basal and cauline; basal leaves several, tufted, petiole slender, elliptic-ovate to oblanceolate, margin crenate or serrate-dentate to pinnately lobed; cauline leaves reduced upwards, linear, grey woolly, uppermost leaves irregularly dissected to subentire

Inflorescence:

heads 6 – 20; peduncles densely tomentose; phyllaries linear, purple-tipped

Flowers:

ligulate florets 6 – 10, 8 – 12 mm long

Fruits:

achenes hirtellous, occasionally glabrous

*KEY TO PACKERA* IN SASKATCHEWAN**
Note: This complex needs taxonomic revision. The key may not be accurate in all cases. Please refer to another key if you encounter difficulty with this one.

1 Plants usually glabrose or glabrate; basal leaves usually entire or dentate, not lobed	2
1 Plants usually tomentose (sometime glabrous) and/ or with basal leaves; basal leaves if present pinnately lobed or dissected	8

2 Ray florets 0 or 8 – 13 (corolla 2 – 7 mm long); plants of northern Saskatchewan	3
2 Ray florets 0 or 5 – 21 (corolla 4 – 12 mm long); plants from various areas of Saskatchewan	4

3 Basal leaves thick; heads few (1-4); involucre purple or at least purple-tipped	P. pauciflora
3 Basal leaves thin; head numerous (8 – 20); involucre green	P. indecora

4 Basal and lower cauline leaves not tapering to petiole, base truncate to cordate	5
4 Basal and lower cauline leaves gradually tapering to petiole	6

5 Basal leaves lanceolate to narrowly ovate, apex acute; margins dentate or serrate	P. pseudaurea
5 Basal leaves cordate, obovate, or ovate, apex rounded; margins crenate, dentate, lobed or wavy	P. streptanthifolia

6 Plants with a taproots and woody caudex; may be tomentose in leaf axils	P. tridenticulata
6 Plants with fibrous roots, taproots or rhizomes; leaves and stems generally all glabrous	7

7 Basal leaves thick, oblanceolate to spatulate; disc florets 35 – 60	P. streptanthifolia
7 Basal leaves thin, lanceolate to elliptic; disc florets 50 – 80	P. paupercula

8 Stems and leaves persistently tomentose	P. plattensis
8 Stems and leaves usually glabrous, sometimes tomentose at base or in leaf axils	9

9 Plants 3 – 10 cm tall; heads few (1-6)	P. cana
9 Plants 10 – 50 cm tall; heads several (6 – 30)	10

10 Basal leaves orbicular to broadly ovate	11
10 Basal leaves narrowly elliptic to oblanceolate	12

11 Margins of basal leaves entire to toothed; involucre glabrous	P. streptanthifolia
11 Margins of basal leaves toothed to pinnatisect; involucre densely tomentose	P. plattensis

12 Basal leaves toothed to lobed, floccose tomentose to glabrescent	P. plattensis
12 Basal leaves entire, except towards dentate apex, white woolly	P. cana