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

Poa arctica spp. arctica is endangered because it is extremely rare and is 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 caespitose, erect, base decumbent, slender to stout, terete or weakly compressed

Leaves:

blades 1.5 – 2.5 mm wide, flat or folded, thin, glabrous; sheaths closed for part of length, terete, glabrous to slightly scabrous; ligules 2 – 4 mm long; auricles absent

Inflorescence:

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

Spikelets:

10 – 40, 3 – 6-flowered, infrequently bulbiferous, laterally compressed

Florets:

glumes lanceolate to ovate, keeled, usually glabrous, 3-veined; callus webbed; lemma lanceolate to ovate, keeled, pubescent on veins, purple; palea villous on keel, usually pubescent in the intercostal region

Fruits:

caryopsis

POA KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Spikelets not compressed; lemmas rounded on back, keel obscure	P. secunda
1 Spikelets compressed laterally; lemmas distinctly keeled	2

2 Plants caespitose, 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 glabrous between the veins	5

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

6 Lemmas glabrous (except for cobwebby hairs at base); leaves filiform	P. cusickii
6 Lemmas pubescent, 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, terete or slightly flattened	P. arida

11 Lemmas greater than 4 mm long, profusely cobwebbed; panicle purplish, violet or greyish; stem leaves usually	12
11 Lemmas less than 4 mm long, cobwebby at base only; panicle 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 filiform or involute	P. pratensis ssp. alpigena