Species: Poa arctica ssp. arctica R. Br.

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Poa arctica ssp. arctica R. Br.

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TAXONOMY

Family:

Poaceae

Genus:

Poa

Species Synonyms:

Poa arctica var. glabriflora Rosh.
Poa arctica ssp. longiculmis Hultén
Poa arctica var. vivipara Hook.
Poa arctica ssp. williamsii (Nash) Hultén
Poa cenisia var. arctica (R. Br.) Richter
Poa longipila Nash
Poa williamsii Nash

Common Names:

arctic bluegrass

DISTRIBUTION

Canada:

Yukon – Mackenzie District – Arctic Island, south to British Columbia – Alberta – northern Saskatchewan – northern Manitoba – northern Ontario – northern Quebec – southern Labrador – Newfoundland

Saskatchewan:

northern Saskatchewan; Cluff Lake – Reindeer River

Ecoregion:

Athabasca Plain, Churchill River Upland

HABITAT

Saskatchewan:

dry pine forests and clearings

Canada:

moist to dry tundra and shores of ponds and streams

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G5T5 S1

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Arctic bluegrass is endangered because it is extremely rare and regionally restricted in Saskatchewan. No threats are known or anticipated.

SPECIES DESCRIPTION

Height:

8 – 50 cm

Roots:

roots fibrous; rhizome usually well-developed, short or long

Stems:

densely to loosely tufted, erect, base bent, slender to stout, round or weakly compressed

Leaves:

blades 1.5 – 2.5 mm wide, flat or folded, thin, hairless; sheaths closed for part of length, round, hairless to slightly rough-hairy; ligules 2 – 4 mm long; ear-like lobes absent

Inflorescence:

4 – 15 cm long, lax to erect, open, branches ascending to widely spreading

Spikelets:

10 – 40, 3 – 6-flowered, infrequently with sterile florets replacing fertile ones, laterally compressed

Florets:

glumes lance-shaped to oval, boat-shaped, usually hairless, 3-veined; hardened thickening below lemma webbed; lemma lance-shaped to oval, boat-shaped, hairy on veins, purple; palea long-hairy on ridge, usually hairy between the veins

Fruits:

grain

POA KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Spikelets not compressed; lemmas rounded on back, ridge obscure	P. secunda
1 Spikelets compressed laterally; lemmas boat-shaped, with a distinct ridge	2

2 Plants tufted, generally lacking rhizomes	3
2 Plants with distinct rhizomes	9

3 Lemmas with cobwebby hairs at base	4
3 Lemmas without cobwebby hairs at base	6

4 Lemmas hairy between the veins	P. glauca ssp. glauca
4 Lemmas hairless between the veins	5

5 Spikelets bronze at tip, relatively dark; inflorescence 13 – 30 cm long; lemma margins distinctly inrolled	P. palustris
5 Spikelets pale; inflorescence 3 – 15 cm long; lemma margins only slightly inrolled if at all	P. interior

6 Lemmas hairless (except for cobwebby hairs at base); leaves thread-like	P. cusickii
6 Lemmas hairy, at least on veins; leaves 1 – 6 mm wide	7

7 Annual, often rooting at the lower nodes; lemma distinctly 5-nerved	P. annua
7 Perennial; lemma with obscure intermediate nerves	8

8 Leaves 3 – 6 mm broad	P. alpina
8 Leaves 1 – 3 mm broad	P. glauca ssp. rupicola

9 Lemmas without cobwebby hairs at base	10
9 Lemmas with cobwebby hairs at base	11

10 Stems solitary or few, strongly flattened	P. compressa
10 Stems tufted, round or slightly flattened	P. arida

11 Lemmas greater than 4 mm long, profusely cobwebbed; inflorescence purplish, violet or greyish; stem leaves usually 1	12
11 Lemmas less than 4 mm long, cobwebby at base only; inflorescence green; stem leaves usually 2 or more	13

12 Ligules ca. 4 mm long; spikelets purplish-grey or brownish	P. arctica ssp. lanata
12 Ligules less than 2 mm long; spikelets purplish or greenish	P. arctica ssp. arctica

13 Basal leaves to 3 mm wide	P. pratensis ssp. pratensis
13 Basal leaves thread-like or inrolled	P. pratensis ssp. alpigena