Lotus unifoliolatus var. unifoliolatus (Hook.) Benth.
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TAXONOMY
 
Family: Fabaceae
Genus: Lotus
 
Species Synonyms: Hosackia americana (Nutt.) Piper
Lotus americanus (Nutt.) Bisch., non Vell.
Lotus purshianus F.E. & E.G. Clem.
Lotus purshianus var. glaber (Nutt.) Munz
Lotus sericeus Pursh, non Moench
Common Names: Spanish clover
prairie trefoil
American bird’s-foot trefoil
 
DISTRIBUTION
 
Canada: southwestern British Columbia, southeastern Saskatchewan – southern Manitoba
Saskatchewan: southeastern Saskatchewan; Souris River Valley, Antler River Valley
Ecoregion: Mixed Grassland, Moist Mixed Grassland, Aspen Parkland
 
HABITAT
 
Saskatchewan: slough bottoms, streamlet margins, and seepy slopes
Associated Species: big bluestem, crane’s bill, foxtail, goldenrod, little blue stem, sedges, short-awn meadow foxtail, slenderleaf collomia, smooth brome
 
RARITY STATUS
 
Provincial Status According
to Harms (2003):
Threatened
Nature Conservancy Status:
G5T5 S2
Saskatchewan Species at
Risk Status:
None
COSEWIC Status:
None
 
Spanish clover is threatened in Saskatchewan because it is rare or uncommon. This species is only somewhat regionally restricted but local population sizes vary. Immediate or probable threats have been identified for this species.
 
SPECIES DESCRIPTION
 
Roots: taproot slender
Stems: annual, herbaceous, erect, 20 – 80 cm tall, branched, hairless to densely hairy
Stipules: gland-like, blackish
Leaves: alternate, subsessile
Leaflets: 3, terminal leaflet stalked, 1 – 3 cm long, to 1.5 cm broad, elliptic to oval, hairy
Inflorescence: flower solitary, bract leaf-like; inflorescence stalk solitary in upper axils, 1 – 2 cm long
Flowers: sepal tube 1.5 – 2 mm long, bell-shaped, teeth mostly more than 2x as long as tube, long hairy; petals white with pink veins, rarely yellowish-white; banner 5 – 7 mm long; wings and keel 4 – 6 mm long
Fruits: legume 2 – 4 cm long, oblong, slightly constricted between the seeds, hairless; seeds olive to light brown, often mottled
 
LOTUS KEY FOR SPECIES FOUND IN SASKATCHEWAN
 
1 Leaves palmately compound, leaflets 5; flowers 5 – 8
L. corniculatus
1 Leaves trifoliately compound, leaflets 3; flowers solitary
L. unifoliolatus var. unifoliolatus