Species: Poa alpina L.

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Poa alpina L.

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TAXONOMY

Family:

Poaceae

Genus:

Poa

Species Synonyms:

Poa alpina ssp. vivipara (L.) Arcang.
Poa vivipara (L.) Willd.

Common Names:

alpine bluegrass

DISTRIBUTION

Canada:

Yukon – Mackenzie District – Keewatin – Ungava – Baffin Island – Labrador, south to British Columbia – Alberta – northern Saskatchewan – Manitoba, Ontario – Newfoundland – Nova Scotia

Saskatchewan:

northern Saskatchewan; Lake Athabasca – Hasbala Lake

Ecoregion:

Tazin Lake Upland, Selwyn Lake Upland

HABITAT

Saskatchewan:

rock outcrops, bouldery tundra, and gravel shores

Associated Species:

poplar, white spruce

RARITY STATUS

Provincial Status According
to Harms (2003):

Endangered

Nature Conservancy Status:

G5 S1

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Alpine bluegrass is endangered because it is rare in Saskatchewan and is restricted to one general region of the province. No threats are known or anticipated.

SPECIES DESCRIPTION

Height:

10 – 40 cm

Roots:

fibrous

Stems:

perennial, densely tufted, erect

Leaves:

blades widely spreading, 1 or 2 on the stem, 1 – 5 cm long, 2 – 6 mm wide, reduced in length upwards flat, hairless or rough-hairy on margins

Inflorescence:

2 – 6 cm long, erect, pyramidal, open to loosely contracted, nodes with 1 – 2 branches, branches ascending to spreading

Spikelets:

4 – 6 mm long, laterally compressed, occasionally with sterile spikelets replacing fertile, containing up to five florets, purplish or bronze

Florets:

glumes lance-shaped to oval, boat-shaped, ridges rough-hairy, at least the lower ones 3-veined; lemmas 3 – 5 mm long, lance-shaped, boat-shaped; paleas boat-shaped, ridge short to long-hairy

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