Argythamnia serrata

(Torrey) Müller Arg.

Linnaea 34: 147. 1865

Common names: Yuma or New Mexico silverbush
Basionyms: Aphora serrata Torrey in W. H. Emory Rep. U.S. Mex. Bound. 2(1): 197. 1859
Synonyms: Argythamnia californica Brandegee A. dressleriana J. W. Ingram A. gracilis Brandegee A. micrandra Croizat A. neomexicana Müller Arg. A. serrata var. magdalenae Millspaugh Ditaxis californica (Brandegee) A. Heller D. dressleriana (J. W. Ingram) Radcliffe-Smith & Govaerts D. gracilis Rose & Standley D. micrandra (Croizat) Radcliffe-Smith & Govaerts D. neomexicana (Müller Arg.) A. Heller D. odontophylla Rose & Standley D. serrata (Torrey) A. Heller D. serrata var. californica (Brandegee) V. W. Steinmann & Felger D. serrata var. magdalenae (Millspaugh) Eastwood
Treatment appears in FNA Volume 12. Treatment on page 178. Mentioned on page 174, 179.
Herbs, annual or perennial, monoecious, to 5 dm. Stems erect or prostrate, usually densely to sparsely hairy, rarely glabrous, hairs malpighiaceous. Leaves: stipules deciduous, ovate, lanceolate to subulate, 0.5–2.3 mm, margins not glandular; petiole 1–10 mm; blade elliptic to ovate, obovate, or narrowly lanceolate, 1–10.5 × 0.2–3 cm, margins serrate, serrulate, or entire, without glands, surfaces usually densely to sparsely hairy, rarely glabrous, hairs malpighiaceous. Inflorescences bisexual, 0.4–1.5 cm; bracts ovate to elliptic, 0.8–2 mm, margins without glands. Flowers without pink dye when wetted. Staminate flowers: sepals lanceolate, 0.9–2.5 × 0.4–1.4 mm; petals elliptic to obovate, 1.5–3.5 × 0.6–2 mm, free from androphore; nectary glands elliptic to oblate, 0.3–0.5 × 0.1–0.2 mm, free from androphore, glabrous; stamens 10, staminodes 0 or 3–5, glabrous. Pistillate flowers: sepals lanceolate to elliptic, 2.3–6.5 × 0.6–1.6 mm, without glands; petals 5, elliptic, 0.7–3 × 0.4–1.6 mm; nectary glands elliptic, 0.4–0.6 × 0.3–0.4 mm, glabrous; ovary sericeous, strigose, or hispidulous; styles 1–1.8 mm, glabrous; stigmas terete. Capsules 1.8–4.5 mm, strigose-hispidulous. Seeds 1.5–2.4 mm, smooth, punctate, striate, or reticulate. 2n = 26 (Baja California Sur, Mexico).

Phenology: Flowering year-round.
Habitat: Desert scrub, sandy, rocky, calcareous soils.
Elevation: 0–1600 m.


V12 71-distribution-map.jpg

Ariz., Calif., Nev., N.Mex., Tex., Mexico, Central America (Guatemala, Nicaragua).


Argythamnia serrata is widely distributed and variable; six species have been described to recognize this variation. However, these groups overlap morphologically and geographically, and many specimens cannot be determined with confidence. A broadly defined A. serrata is therefore recognized here.



Lower Taxa

No lower taxa listed.