Species: Ranunculus hyperboreus var. hyperboreus Rottb.

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Ranunculus hyperboreus var. hyperboreus Rottb.

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TAXONOMY

Family:

Ranunculaceae

Genus:

Ranunculus

Species Synonyms:

none

Common Names:

large nodding buttercup
boreal buttercup
far-northern buttercup

DISTRIBUTION

Canada:

Yukon – Mackenzie District – Keewatin District – Arctic Island, south to British Columbia – southwestern Alberta – northwestern Saskatchewan – northern Manitoba – northern Ontario – Ungava – eastern Quebec – Labrador – northern Newfoundland

Saskatchewan:

northeastern Saskatchewan; Lake Athabasca

Ecoregion:

Athabasca Plain

HABITAT

Saskatchewan:

shallow beach pools and wet sand on lake and stream shores

Canada:

shallow fresh or brackish waters

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G5 S1

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Ranunculus hyperboreus var. hyperboreus is endangered because of extreme rarity in Saskatchewan. It is restricted to one small region of the province and most local populations are small. No immediate threats are known but may occur in the future.

SPECIES DESCRIPTION

Roots:

fibrous

Stems:

prostrate or floating, rooting at the lower nodes, branching

Leaves:

basal leaves absent; cauline leaves 3 – 12 mm long, 5 – 21 mm wide, reniform to flabellate, deeply 3-lobed, vase obtuse to cordate, lobed undivided, terminal segment entire or distantly crenulate, lateral lobes 2-lobed

Inflorescence:

flowers solitary; receptacle elongating in fruit, developing into head of achenes

Flowers:

receptacle glabrous; sepals 3 – 4, spreading or reflexed, glabrous; petals 3 – 4, obovate, yellow; nectary on petal surface; stamens many; carpels many on a receptacle

Fruits:

heads of achenes globose; achenes 20 – 60, glabrous, beak linear

RANUNCULUS KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Petals white; aquatic plants with all leaves submersed	R. aquatilis var. diffusa
1 Petals yellow; mostly terrestrial plants or not strictly aquatic (except R. gmelinii)	2

2 Achenes with 3 or 4 longitudinal nerves; leaves crenate; plants stoloniferous	R. cymbalaria
2 Achenes not nerved longitudinally; leaves various; plants not stoloniferous	3

3 Basal leaves entire to slightly lobed, upper leaves similar or absent	4
3 Basal leaves distinctly toothed, lobed or divided OR if entire, cauline leaves deeply lobed or cleft and unlike the basal leaves OR basal leaves absent	5

4 Leaves linear and essentially bladeless or blades linear-lanceolate	R. flammula var. reptans
4 Leaves with well-developed lanceolate to oval blades	R. flammula var. ovalis

5 Sepals 3 or 4; leaves reniform	6
5 Sepals 5; leaves of various shapes	7

6 Plants at least partially aquatic, < 5 cm high; leaves to 1 cm wide; achenes not constricted, nearly beakless	R. hyperboreus var. hyperboreus
6 Plants terrestrial, 10 – 20 cm high; leaves to 5 cm wide; achenes constricted near the middle, beak hooked	R. lapponicus

7 Plants strictly aquatic, weak stems floating	R. gmelinii
7 Plants not strictly aquatic	8

8 Beaks of achenes minute, achene corky-thickened towards base; plant fleshy; lower leaves petioled	R. sceleratus
8 Beaks of achenes distinct, achene not corky-thickened towards base; plants not fleshy; lower leaves more or less all sessile	9

9 Basal leaves entire to crenate or shallowly 3 – 5-lobed, cauline leaves cleft or divided	10
9 Basal leaves deeply dissected, the lobes often toothed	15

10 Sepals densely reddish-brown pilose in part; stems usually 1-flowered	R. nivalis
10 Sepals glabrous or white-pubescent; stems usually 2 – many-flowered	11

11 Fruiting heads cylindrical	12
11 Fruiting heads globose	13

12 Achenes to 150 per aggregate, finely pubescent; plants hairy; petals 5 – 9 mm long	R. glaberrimus var. ellipticus
12 Achenes to 50 per aggregate, glabrous; plants glabrous; petals 6 – 15 mm long	R. rhomboideus

13 Petals 1.5 – 3 mm long; basal leaves reniform	R. abortivus
13 Petals greater than 3 mm long; basal leaves circular or cordate	14

14 Flower stalks stout; petals 8 – 15 mm long; stems and leaves pilose or villose	R. cardiophyllus
14 Flower stalks slender; petals 3 – 8 mm long; stems and leaves nearly glabrous	R. inamoenus var. inamoenus

15 Achenes slightly flattened, beaks slender; receptacle in fruit 4 times its length in flower	R. pedatifidus var. affinis
15 Achenes very strongly flattened, beaks stout; receptacle in fruit < 3 times its length in flower	16

16 Petals 5 – 15 mm long, noticeably longer than sepals; sepals spreading; terminal segment of larger leaves sessile	R. acris var. acris
16 Petals 4 – 5 mm long, shorter than or barely surpassing sepals; sepals reflexed; terminal segment of larger leaves stalked	17

17 Stems reclining or prostrate, often rooting at lower nodes; petals equalling or longer than sepals, deep yellow; sepals purplish; heads of achenes ovoid to globose	R. macounii
17 Stems erect, not rooting at the nodes; petals shorter than sepals, pale yellow; sepals yellowish; heads of achenes cylindrical	R. pensylvanicus