Astragalus kentrophyta var. kentrophyta Gray
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TAXONOMY
 
Family: Fabaceae
Genus: Astragalus
 
Species Synonyms: Astragalus viridis (Nutt.) Sheldon
Kentrophyta montana Nutt.
Common Names: spiny milkvetch
prickly milkvetch
Nuttall’s kentrophyta
 
DISTRIBUTION
 
Canada: southern Alberta – southern Saskatchewan
Saskatchewan: southwestern Saskatchewan; Great Sand Hills
Ecoregion: Mixed Grassland
 
HABITAT
 
Saskatchewan: active to semi-stabilized sand dune flats
Associated species: Achnatherum hymenoides, Elaeagnus commutata, Grindelia squarrosa, Heterotheca villosa, Koeleria macrantha, Lupinus pusillus, Psoralidium lanceolatum, Sporobolus cryptandrus
 
RARITY STATUS
 
Provincial Status According
to Harms (2003):
Threatened
Nature Conservancy Status:
G5T4 N2T2 S1
Saskatchewan Species at
Risk Status:
Threatened
COSEWIC Status:
None
 
Astragalus kentrophyta var. kentrophyta is threatened in Saskatchewan because it is rare and highly regionally restricted in the province. Local population sizes vary. Possible threats have been identified for this species.
 
SPECIES DESCRIPTION
 
Roots: taproot strong
Stem: prostrate, branched, 10 – 40 cm long, loosely or densely matted, canescent or loosely strigose, hairs dolabriform or basifixed
Stipules: 1.5 – 6 mm long, spinulose
Leaves: petiole 0 – 4 mm long; 7 – 25 mm long, pinnate
Leaflets: 5 – 7, linear, stiff, spine-tipped, rigid and prickly, silky-strigose
Inflorescence: racemes axillary, 1 – 4-flowered; pedicels < 1.8 mm long; peduncle very short, usually concealed by stipules
Flowers: calyx tube 2 – 2.5 mm long; corolla 4 – 6 mm long, yellowish white with a purplish tinge; banner 4 – 5 mm long, arched; wings 3.5 – 5 mm long; keel 3 – 4 mm long
Fruits: legume 4 – 7 mm long, elliptic, laterally compressed, strigulose; seeds 1 – 3, 2 – 3 mm long, brownish to blackish, smooth, pitted
 
ASTRAGALUS KEY FOR GENERA FOUND IN SASKATCHEWAN
 
1 Leaves needle-like, distinctly spine-tipped
A. kentrophyta var. kentrophyta
1 Leaves not needle-like or spine-tipped
2
   
2 Plants acaulescent, < 10 cm tall, densely caespitose; flowers often included among leaves
3
2 Plants caulescent, > 10 cm tall, stems evident, may be erect or decumbent (subacaulescent in A. missouriensis); flowers in distinct inflorescences
6
 
3 Leaves simple or with 1 or 2 linear leaflets
A. spatulatus
3 Leaves pinnate or trifoliate
4
 
4 Leaves trifoliate
A. gilviflorus var. gilviflorus
4 Leaves pinnate
5
 
5 Leaf pubescence dolabriform; leaflets 4 – 5x as long as wide, apex acute
A. lotiflorus
5 Leaf pubescence basifixed; leaflets 2x as long as wide, apex rounded
A. purshii var. purshii
 
6 Leaf pubescence dolabriform
7
6 Leaf pubescence basifixed
9
 
7 Corolla greenish-white or ochroleucus; plants green
A. canadensis var. canadensis
7 Corolla purplish; plants covered in greyish or silvery hairs
8
 
8 Leaflets up to 12 pairs; plants definitely caulescent; stipules connate
A. adsurgens ssp. robustior
8 Leaflets fewer than or equal to 7 pairs; plants subacaulescent; stipules distinct
A. missouriensis var. missouriensis
 
9 Petals yellow, cream or orange, keel occasionally blue-tinged
10
9 Petals blue, pink, or purple
18
 
10 Leaves and stems gray-hirsute, hairs 1 – 2 mm long, widely spreading
A. drummondii
10 Pubescence of leaves and stem variable but hairs shorter than 1 mm long
11
   
11 Pods glabrous or nearly to
12
11 Pods distinctly pubescent
15
 
12 Pods sessile or nearly so, stipe < 1 mm long; pods very fleshy, walls thick, hard and bony when dry
A. crassicarpus
12 Pods stipitate, stipe equal to or exceeding calyx; pods not fleshy, walls thin
13
 
13 Pods linear
A. racemosus var. racemosus
13 Pods broader
14
 
14 Leaflets 2 – 4 cm long; pods inflated and nearly terete
A. americanus
14 Leaflets < 2 cm long; pods very strongly compressed
A. tenellus
 
15 Flowers small, calyx tube 1.5 – 4.5 mm long, banner 4 – 12.5 mm long
16
15 Flowers large, calyx tube > 4.5 mm long, banner > 13 mm long
17
 
16 Pods pendulous, stipitate
A. alpinus var. alpinus
16 Pods erect, short-stipitate
A. bodinii
 
17 Leaflets without petiolules; pods sessile
A. pectinatus
17 Leaflets with petiolules; pods stipitate
A. agrestis
 
18 Pods 1 – 3 cm long
19
18 Pods generally less than 1.1 cm long
20
 
19 Pods with two deep grooves on upper side
A. bisulcatus
19 Pods lacking two deep grooves
A. flexuosus var. flexuosus
   
20 Pods spreading to erect
21
20 Pods spreading to deflexed
22
 
21 Flowers small, calyx tube < 4.5 mm long, banner < 13 mm long
A. bodinii
21 Flowers large, calyx tube > 4.5 mm long, banner > 13 mm long
A. agrestis
 
22 Pods plump
A. gracilis
22 Pods strongly compressed laterally
23
 
23 Racemes at most loosely 10-flowered; peduncles shorter than or only slightly surpassing leaves
A. vexilliflexus var. vexilliflexus
23 Racemes usually more than 10-flowered; peduncles longer than leaves
A. eucosmus