Species: Potentilla hookeriana ssp. hookeriana Lehm.

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Potentilla hookeriana ssp. hookeriana Lehm.

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TAXONOMY

Family:

Rosaceae

Genus:

Potentilla

Species Synonyms:

Potentilla nivea ssp. hookeriana (Lehm.) Hiitonen

Common Names:

Hooker’s cinquefoil

DISTRIBUTION

Canada:

Yukon – Mackenzie District – Keewatin District, south to southeastern British Columbia – southwestern and northeastern Alberta – northwestern Saskatchewan

Saskatchewan:

northwestern Saskatchewan; Lake Athabasca

Ecoregion:

Tazin Lake Upland

HABITAT

Saskatchewan:

rock outcrops and slopes above shores

Canada:

dry calcareous rocks and slopes

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G5T4 S1

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Hooker’s cinquefoil is endangered because it is extremely rare and highly regionally restricted in Saskatchewan. No threats are known or anticipated at the present time.

SPECIES DESCRIPTION

Height:

to 40 cm

Stems:

stem base persistent, woody, thick; stems few, erect

Leaves:

basal leaves divided into threes, green, long hairy above, densely woolly and long hairy below; leaf stalks less than 3 times as long as blade, short hairy with spreading, straight, white hairs

Leaflets:

broad, mostly egg-shaped, slightly leathery, white-woolly, coarsely toothed or lobed, terminal tooth longer than lateral teeth

Inflorescence:

few to several-flowered, not very leafy

Flowers:

sepals oval to lance-shaped; petals exceeding the sepals, yellow, inversely heart-shaped

Fruits:

one-seeded, hairless

POTENTILLA KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Basal or lower stem leaves divided into threes	2
1 Basal or lower stem leaves pinnately or palmately compound with at least 5 leaflets	7

2 Inflorescences leafy, many-flowered; petals shorter than or scarcely exceeding the sepals	3
2 Inflorescences not very leafy, few-flowered; petals greatly exceeding the sepals	4

3 Petals about half as long as sepals; stamens 10; stems soft-hairy below	P. rivalis var. millegrana
3 Petals almost equal to the sepals; stamens commonly 20; stems stiffly straight hairy below	P. norvegica ssp. monspeliensis

4 Leaf stalks bearing tufts of long, tangled hairs, straight hairs lacking	5
4 Leaf stalks with at least some straight, spreading hairs	6

5 Leaflets coarsely toothed but not lobed	P. nivea ssp. nivea
5 Leaflets divided into narrow lobes	P. nivea ssp. pentaphylla

6 Leaf stalks up to 3 times as long as blade, with long and short hairs	P. hookeriana ssp. hookeriana
6 Leaf stalks more than 3 times as long as blade, with long hairs only	P. hookeriana ssp. chamissonis

7 Lower leaves palmately compound	8
7 Lower leaves pinnately compound	14

8 Leaves densely white-woolly beneath	9
8 Leaves hairless or hairy but not white-woolly	12

9 Basal leaflets divided into comb-like segments well over half way to midrib, lobes linear	P. gracilis var. flabelliformis
9 Basal leaflets deeply toothed or lobed, but not well over half way to midrib, teeth oval or lobes wider	10

10 Flowers to 1 cm broad; stem less than 20 cm tall; leaves never greenish above	P. concinna var. concinna
10 Flowers greater than 2 cm broad; stems to 70 cm tall; leaves mostly greenish above	11

11 Leaflets greyish-woolly beneath, margin finely saw-toothed or lobed	P. gracilis var. pulcherrima
11 Leaflets white-woolly, margin coarsely saw-toothed	P. gracilis var. gracilis

12 Petals shorter than the sepals	P. rivalis var. pentandra
12 Petals longer than the sepals	13

13 Leaflet margins entire at the base; anthers usually 0.5 mm long	P. diversifolia var. diversifolia
13 Leaflet margins toothed to base; anthers usually 1.0 mm long	P. gracilis var. fastigiata

14 Plants glandular, long-hairy; style inserted near middle of fruit	P. arguta ssp. arguta
14 Plants not glandular and long-hairy; style inserted near top of fruit	15

15 Inflorescences very leafy, many-flowered; annuals or biennials	16
15 Inflorescences not as leafy, few-flowered; perennials	17

16 Lower leaves with 5 – 11 leaflets; fruits with a corky protuberance	P. paradoxa
16 Lower leaves with 5 leaflets; fruits smooth	P. rivalis var. rivalis

17 Style shorter than or equal to mature fruit	18
17 Style thread-like and distinctly longer than mature fruit	21

18 Style lacking glands at base	P. bimundorum
18 Style glandular and thickened at base	19

19 Leaflets hairless beneath	P. pensylvanica var. glabrata
19 Leaflets white-woolly beneath	20

20 Leaflets whitish beneath, silvery-silky above	P. bipinnatifida
20 Leaflets greyish beneath, greyish and stiff-hairy above	P. pensylvanica var. pensylvanica

21 Leaflets dissected nearly to midrib; stems commonly 20 cm tall	P. plattensis
21 Leaflets dissected at most about halfway to the midrib; stems about 50 cm tall	22

22 Bractlets half as long as sepals, linear	P. hippiana var. filicaulis
22 Bractlets nearly as long and wide as sepals	23

23 Leaflets loosely woolly and dull	P. hippiana var. argyrea
23 Leaflets silky and shiny	P. hippiana var. hippiana