Scoparia montevidensis

Perennials. Stems decumbent, spreading, ascending, or erect, sometimes rooting at nodes, usually much-branched proximally, 10–30 cm, glabrous or distally sparsely glandular-puberulent. Leaves: blade oblanceolate to narrowly oblanceolate, sometimes linear, 5–25 × 0.4–8 mm, base tapered, margins dentate to pinnately lobed, sometimes entire. Inflorescences: flowers 1 or 2 per axil; bracts narrowly oblanceolate to linear, 2–20 mm. Pedicels 6–17 mm, glabrous or sparsely glandular-puberulent. Flowers: calyx lobes 5, ovate to lanceolate, 1.6–2.2 × 0.5–0.7 mm; corolla yellow or orangish yellow, 2.5–2.9 × 3–4.5 mm. Capsules ovoid, 2.2–4 × 1.3–2.5 mm. Seeds: faces 0.2–0.4 mm.

Phenology: Flowering Apr–Jul.
Habitat: Sandy, disturbed areas, including vacant lots, roadsides, ballast.
Elevation: 0–100 m.

Introduced; Fla., N.C., Mexico (Veracruz), Central America, South America.

Discussion

R. Chodat (1908) noted the polymorphic nature of Scoparia montevidensis and emphasized habit, leaf margin, and pedicel characters in distinguishing seven varieties. These characters appear to vary freely among South American plants, making the application of infraspecific names of questionable value. The name var. glandulifera has been applied to some specimens in the flora area with glandular-puberulent pedicels. A specimen collected in 1874 on ballast at Kaighn Point in Camden, New Jersey (C. F. Parker s.n., MO) was annotated by F. W. Pennell in 1934 as S. flava. He later cited that specimen, the only collection from New Jersey, as S. montevidensis (Pennell 1935), apparently adopting a concept of that species that included S. flava, an approach that is followed here.

Selected References

None.

Lower Taxa