Duration: Perennial
Nativity: Non-native
Lifeform: Forb/Herb
General: Perennial herb, 40-70 cm tall, forming colonies from deep rhizomes; stems erect, more or less canescent toward the top.
Leaves: Alternate and pinnately compound, 3-10 cm long, with 15-25 leaflets; leaflets oblong-ovate, 3-18 mm long and 1-7 mm wide, glabrous on the upper surface and strigose on the lower surface.
Flowers: Attractive red-orange pea-flowers; arranged in racemes, 2-9 cm long, from the leaf axils; flowers 12-14 mm long; calyx bell-shaped, 5-6 mm long, white-hairy, topped with 5 triangular teeth; petals 5, in papilionaceous configuration (i.e. pea-flowers) with a lower keel-shaped petal which wraps around the stigma and stamens, two lateral wing petals, and a larger, upper banner petal. Petals are brick-red, drying lavender to brown.
Fruits: Pods are ovoid and bladdery-inflated, 13-24 mm long, with thin papery walls; on a stipe (small stalk between the persistent calyx and the base of the pod) 4-7 mm long.
Ecology: Found in disturbed ground, often on roadsides, from 4,000-8,500 ft (1372-2591 m); flowers May-July.
Distribution: Native to Asia; introduced and occasional throughout w US.
Notes: With its pea-flowers, bladdery-inflated pods on short stipes, and odd-pinnately compound leaves, this rhizomatous perennial can easily be mistaken for an Astragalus. In fact, it has twice been formally (and mistakenly) described by botanists as a native, newly discovered Astragalus (it is introduced from Asia and not particularly common in the US). Distinguish it by its brick-red flowers which fade to a light brown-purple color when they dry; its tendency to grow in colonies, thanks to the deep-seated rhizomes; and its habitat along roadsides and irrigation ditches. Another character that sets it apart from Astragalus is its style, which is barbellate (with short, stiff hairs or barbs) below the stigma; Astragalus spp. have glabrous styles.
Ethnobotany: In China it is used as a folk medicine for treatment of hypertension.
Etymology: Sphaerophysa is from the Greek sphaira, globe, and physa, a bladder or bubble, alluding to the seed pods; salsula means salty, and refers to the alkaline habitat in which the plant can grow.
Synonyms: Swainsona salsula, Phaca salsula
Editor: AHazelton 2017
Plant: perennial, spreading by root sprouting; stem ascending, 4-15 dm
Leaves: odd-1-pinnate; leaflets 15-23, 0.6-2 cm, oblong to ovate
INFLORESCENCE: raceme, axillary; bractlets at base of calyx; pedicels 3-7 mm
Flowers: calyx lobes subequal, < tube; corolla 12-14 mm, brick- or orange-red, keel > wings; 9 filaments fused, 1 free; style hairy at tip
Fruit: legume, spreading or reflexed, 1.4-2.4 cm, spheric to ovoid, grooved on upper side, papery or membranous, often mottled, glabrous; stalk-like base 4-7 mm; Seeds many
Misc: Cult fields, disturbed sites; < 500 m.
