Parthenium argentatum

A. Gray in W. H. Emory
in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 86. 1859.
Common names: Guayule
Treatment appears in FNA Volume 21. Treatment on page 21. Mentioned on page 20.

Shrubs, 30–100+ cm. Leaf blades lanceolate to oblanceolate, 15–25(–40+) × 6–15(–25+) mm, margins mostly entire, some with 1–2(–5) sharp teeth, faces densely strigillose (gray to white) and obscurely or not at all gland-dotted. Heads radiate, in glomerules of 3–5+ at ends of ± ebracteate stalks 8–15(–20+) cm. Peduncles 1–2(–6+) mm. Phyllaries: outer 5 oval-elliptic, 2.5–3+ mm, inner 5 ± orbiculate, 3.5–4 mm. Pistillate florets 5; corolla laminae ovate, 1.2–1.5 mm. Disc florets 20–30+. Cypselae ± obovoid, 2.5–3 mm; pappus-like enations 2(–4), erect to spreading, ± subulate, 0.3–0.8 mm. 2n = 36.


Phenology: Flowering Apr–Jun.
Habitat: Calcareous soils
Elevation: 1000–1500 m

Discussion

Guayule has sometimes been used for commercial production of natural rubber. Hybrids between Parthenium argentatum and P. incanum have been noted.

Selected References

None.

Lower Taxa

None.

... more about "Parthenium argentatum"
John L. Strother +
A. Gray in W. H. Emory +
Guayule +
Tex. +  and Mexico. +
1000–1500 m +
Calcareous soils +
Flowering Apr–Jun. +
in W. H. Emory, Rep. U.S. Mex. Bound. +
Undefined (tribe Undefined) subtribe Ambrosieae +  and Undefined (tribe Undefined) subtribe Iveae +
Parthenium argentatum +
Parthenium +
species +