Species: Oxytropis lambertii var. lambertii Pursh

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Oxytropis lambertii var. lambertii Pursh

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TAXONOMY

Family:

Fabaceae

Genus:

Oxytropis

Species Synonyms:

Oxytropis involuta (A. Nels.) K. Schum.

Common Names:

purple locoweed
Lambert’s locoweed

DISTRIBUTION

Canada:

southeastern Saskatchewan – southern Manitoba

Saskatchewan:

southeastern Saskatchewan; Souris and Antler River Valleys

Ecoregion:

Moist Mixed Grassland, Aspen Parkland

HABITAT

Saskatchewan:

gravely prairie slopes and summits or river bluffs

Associaterd species:

green needlegrass, hairy goldenaster, Kentucky bluegrass, phlox, purple milkvetch

RARITY STATUS

Provincial Status According
to Harms (2003):

Vulnerable

Nature Conservancy Status:

G5 S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Purple locoweed is vulnerable in Saskatchewan because it is rare or uncommon and is restricted to a small region of the province. Local population sizes vary and possible threats have been identified for this species.

SPECIES DESCRIPTION

Roots:

taproots stout

Stems:

caudex knobby or branching; stem absent

Stipules:

fused for more than 4 mm

Leaves:

odd-pinnate, of two types, principal leaves 10 – 17 cm long, hairs attaching in the middle, hairs long

Leaflets:

7 – 19, 0.5 – 4 cm long, linear to elliptic, tip acute to long-tapered

Inflorescence:

unbranched, 10 – 20-flowered, flowers spreading to erect; inflorescence stalk erect, 5 – 30 cm long

Flowers:

sepal tube 6 – 7 mm long, long hairy, occasionally with blackish hairs; petals reddish-purple; banner 15 – 25 mm long; wings 12 – 20 mm long, tip square; keel 13 – 19 mm long

Fruits:

pod sessile or short-stalked, 8 – 15 mm long, ovoid, beak straight to divergent, silky-hairy; seeds 2 mm long, brown, smooth

OXYTROPIS KEY FOR SPECIES FOUND IN SASKATCHEWAN

1 Leaflets in groups of three or more, appearing whorled	O. splendens
1 Leaflets opposite or subopposite	2

2 Plants with a definite stem (with one or more nodes); flowers and pods reflexed	O. deflexa var. sericea
2 Plants lacking a definite stem, inflorescence stalks long and appearing stem-like but without leaves; flowers and pods ascending to erect	3

3 Petals white, cream-coloured, or yellow	4
3 Petals purplish or blue	5

4 Leaflets densely silky hairy, < 15; keel 15 – 20 mm long; pods leathery	O. campestris var. spicata
4 Leaflets sparsely hairy, > 15; keel 11 – 15 mm long; pods papery	O. monticola

5 Hairs attaching in the middle, one side usually shorter than the other	O. lambertii var. lambertii
5 Hairs attaching at the base	6

6 Leaves of two kinds; sepal hairs not shaggy; petals blue or purple	O. campestris var. dispar
6 Leaves of one kind; sepal hairs quite shaggy; petals bright pink-purple, may dry blue	O. besseyi var. besseyi