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 glanddotted. 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; pappuslike 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"
not tailed +, rounded +  and obtuse +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
paniculiform +  and corymbiform +
indeterminate +  and determinate +
John L. Strother +
A. Gray in W. H. Emory +
decurrent +
compound +  and simple +
lobed;spatulate;rounded-deltate;ovate;obovate;oblanceolate;lyrate;lanceolate +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Guayule +
ochroleucous +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
villous +, strigillose +, hispidulous +, glabrous +  and warty +
scabrellous +  and tuberculate +
fertile +  and bisexual +
Tex. +  and Mexico +
1000–1500 m +
subulate +  and pappuslike +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
15 cm150 mm <br />0.15 m <br /> (20 cm200 mm <br />0.2 m <br />) +
strigillose +
winged +  and beaked +
dispersed +
Calcareous soils +
in corymbiform , glomerate , paniculiform , racemiform or spiciform , arrays +  and singly +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
less scarious +  and membranous +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
hemispheric +
conspicuous +
oblong +  and reniform or orbiculate or more or less coroniform +
2.5 cm25 mm <br />0.025 m <br /> (4 cm40 mm <br />0.04 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
sessile +  and petiolate +
deltate +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
herbaceous +  and scarious +
2-carpellate +
peripheral +
papillate +
fimbrillate;cuneate;flabelliform +
membranous +  and scarious +
persistent +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
Flowering Apr–Jun. +
unequal +  and subequal +
in W. H. Emory, Rep. U.S. Mex. Bound. +
bearing subulate enations +, hairy +  and bristly +
exalbuminous +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Undefined (tribe Undefined) subtribe Ambrosieae +  and Undefined (tribe Undefined) subtribe Iveae +
Parthenium argentatum +
Parthenium +
species +
campanulate +  and cylindric +
toothed +  and entire +
perennial +, biennial +  and annual +