Astragalus nuttallianus Dc.
Family: Fabaceae
smallflowered milkvetch,  more...
Astragalus nuttallianus image
Max Licher  
Wiggins 1964, Kearney and Peebles 1969, Martin and Hutchins 1980, Cronquist et al. 1989 (Intermountain Flora), Allred and Ivey 2012, Heil et al. 2013
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Low, spreading annual or winter-annual herb, from a slender taproot; stems slender, prostrate or weakly ascending, 3-25 cm long; herbage covered with straight, white, appressed hairs. Leaves: Alternate and pinnately compound, 2-7 cm long, with 7-19 leaflets per leaf; leaflets linear-elliptic to obcordate, 2-14 mm long, with entire margins, the lower surface often hairier than the upper surface; stipules 1-6 mm long, distinct. Flowers: Purple and white, in few-flowered congested racemes up to 2 cm long, with the flowers pointing upward (ascending) or downward (declined) at maturity; flowers 4-10 mm long, with pea-flower morphology (papilionaceous), with a wide upper petal called the banner, two smaller lateral petals called the wings, and a boat-shaped lower petal called the keel which contains the style and stamens. Petals whitish, lilac, or pink-purple, with the banner petal recurved 40- 45 degrees; sepals 5, loosely strigose, united into a tube 2-3 mm long, topped with 5 narrow teeth, 2 mm long. Fruits: Pods ascending, spreading, or declined, linear and curved into a crescent shape, 1.5-2 cm long, 2-3 mm wide, bilocular, strigose to glabrous. Ecology: Found on arid plains and on hillsides, mesas, and slopes, below 6,500 ft (1981 m); flowers February-May. Distribution: CA, NV east to KA, AR and LA; south to c MEX. Notes: This species is variable in size. Stems may be only a few cm long and ascending, or longer and laxly spreading on the ground. It is one of the smaller, more delicate annual Astragalus species; distinguished by the appressed, white or silvery hairs all over; pinnately compound, gray-green leaves; small purple pea flowers less than 1 cm long; and seed pods that are long and narrow, flattened, and curved into an crescent-shape. Other important key characters are the bilocular pod (cut it in half cross-wise and there are 2 chambers) without a stipe or gypopore (this would be a stalk at the base of the pod but above the calyx attachment point); stipules distinct, not fused to each other and wrapping around the stem; and simple, non-branching hairs. This species has ten known varieties (Barneby 1964) in the region. Ethnobotany: Unknown Etymology: Astragalus comes from the Greek astragalos, ankle bone, an early name applied to some plants in this family because of the shape of the seeds; nuttallianus is named for Thomas Nuttall (1786-1859) an English botanist. Editor: SBuckley 2010, FSCoburn 2015, AHazelton 2017
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Liz Makings  
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Patrick Alexander  
Astragalus nuttallianus image
Patrick Alexander  
Astragalus nuttallianus image
Patrick Alexander  
Astragalus nuttallianus image
Patrick Alexander  
Astragalus nuttallianus image
Patrick Alexander  
Astragalus nuttallianus image
Patrick Alexander  
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Anthony Mendoza  
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Sue Carnahan  
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Anthony Mendoza  
Astragalus nuttallianus image
Anthony Mendoza  
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Sue Carnahan  
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Anthony Mendoza  
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Kirstin Phillips  
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Kirstin Phillips  
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