Guilleminea densa var. aggregata

Uline & W. L. Bray

Bot. Gaz. 20: 343. 1895

Common names: Small matweed
Treatment appears in FNA Volume 4. Treatment on page 438.
Plants 1–8 dm diam. Stems procumbent, 0.5–1.5 mm diam., villous to densely woolly-villous. Leaves basal and cauline; basal rosette leaves with winged petiole 8–20 mm, blade oblong-elliptic to lanceolate, (8–)20–40 × (1–)6–9 (–13) mm, glabrous adaxially, villous abaxially; cauline leaves with petiole 2–4 mm, blade broadly to narrowly ovate, oblong-ovate, oblong, rhombic, or occasionally elliptic to lanceolate, 2–10(–23) × 2–8(–14) cm, glabrous adaxially, villous to woolly-villous abaxially. Inflorescences white, 2–3 × 3–5 mm. Flowers sessile; calyx tubes 0.8–1.2 mm; tepal lobes whitish, ovate to elliptic, 0.8–1.5 mm, membranaceous, apex acute to rounded, abaxially villous (at least near base). Utricles included within tepals, 1.1–1.4 mm. Seeds 0.8–0.9 × 0.6–0.7 mm.

Phenology: Flowering spring–fall.
Habitat: Dry sandy, gravelly, sandstone areas, waste places
Elevation: (0-)1200-2600 m


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Ariz., Calif., Colo., N.Mex., Okla., Tex., Mexico.


Guilleminea densa var. aggregata has been reported also from Maryland and South Carolina; I have seen no specimens to support those reports.

Selected References


Lower Taxa