Alternanthera paronychioides

A. St.-Hilaire

Voy. Distr. Diam. 2: 439. 1833. 1833

Common names: Smooth joyweed
Introduced
Basionyms: Illecebrum ficoideum Jacquin Select. Stirp. Amer. Hist., 88. 1763,
Treatment appears in FNA Volume 4. Treatment on page 450. Mentioned on page 448.

Herbs, perennial, 1–8 dm. Stems prostrate, villous, glabrate. Leaves sessile; blade elliptic, ovate-rhombic, or oval, 0.6–2.5 × 0.3–1.1 cm, apex acute or obtuse, villous, soon glabrate. Inflorescences axillary, sessile; heads white, globose, 0.5–1 cm diam.; bracts less than 1/2 as long as tepals. Flowers: tepals monomorphic, white, lanceolate, 3–5 mm, apex acuminate, without rigid, spinose tips, hairs not barbed; stamens 5; anthers 3–5, globose; pseudostaminodes ligulate, shorter than filaments, margins entire or dentate. Utricles included within tepals, stramineous, orbiculate to rounded-obovate, 2–2.3 mm, apex truncate. Seeds lenticular, 1.2–1.5 mm.


Phenology: Flowering spring–late fall, year-round in far south.
Habitat: Ballast ground, swamps, sandy places, limestone near salt water
Elevation: 0-10 m

Distribution

V4 885-distribution-map.gif

Introduced; Ala., Del., Fla., Ga., La., Miss., N.J., N.C., Pa., S.C., Tenn., Tex., Mexico, West Indies, Central America, South America, Asia, Africa, Pacific Islands.

Discussion

Plants identified as Alternanthera paronychioides var. amazonica Huber have been collected on salt flats in central Louisiana. The specimens I have seen are not sufficiently distinct to warrant varietal recognition.

Selected References

None.

Lower Taxa

None.

Steven E. Clemants +
A. St.-Hilaire +
Illecebrum ficoideum +
Smooth joyweed +
Ala. +, Del. +, Fla. +, Ga. +, La. +, Miss. +, N.J. +, N.C. +, Pa. +, S.C. +, Tenn. +, Tex. +, Mexico +, West Indies +, Central America +, South America +, Asia +, Africa +  and Pacific Islands. +
0-10 m +
Ballast ground, swamps, sandy places, limestone near salt water +
Flowering spring–late fall, year-round in far south. +
Voy. Distr. Diam. +
Introduced +
Alternanthera paronychioides +
Alternanthera +
species +