Tithonia thurberi

A. Gray

Proc. Amer. Acad. Arts 8: 655. 1873.

Common names: Arizona sunflowerweed
Illustrated
Synonyms: Tithonia palmeri Rose
Treatment appears in FNA Volume 21. Treatment on page 139.

Annuals, 70–200 cm. Leaves: petioles 0–3.3 cm; blades deltate, 7–28 × 5.5–21.5 cm, abaxial faces sparsely hirsute (hairs larger on veins). Peduncles 17–36 cm. Phyllaries 13–16 in 3 series, linear to spatulate; outer 8–15 × 2.5–4.5 mm, apices acute, abaxial faces puberulent; inner 12–15.5 × 3.5–7 mm, apices acute, abaxial faces glabrous. Paleae 11–16.5 × 2–4 mm, mucros 3 mm. Ray-florets 7–10; corollas yellow, laminae oblong, 9–15 × 4–6 mm. Disc-florets 40–60. Cypselae 6–9 mm. 2n = 34.


Phenology: Flowering Aug–Sep.
Habitat: Disturbed areas, canyons, watercourses
Elevation: 900–1000 m

Discussion

Selected References

None.

Lower Taxa

None.
... more about "Tithonia thurberi"
glabrous +, puberulent +  and hirsute +
not tailed +, rounded +  and obtuse +
pale +  and dark +
connate +  and distinct +
subequal +
scarious +
usually ovate +  and lanceolate +
usually deltate +  and lanceolate +
indeterminate +  and determinate +
John C. La Duke +
A. Gray +
auriculate +  and truncate +
5-nerved +  and 3-nerved +
7 cm70 mm <br />0.07 m <br /> (28 cm280 mm <br />0.28 m <br />) +
deltate +
5.5cm;21.5cm +
winged;ribbed;winged;ribbed +
tuberculate +  and rugose +
barbellulate +  and barbellate +
Arizona sunflowerweed +
hairy +  and glabrous +
cuneiform +, biconvex +, 4-angled +, 3-angled +, flattened +  and compressed +
fertile +  and bisexual +
fertile +  and bisexual +
Ariz. +  and Mexico (Sonora) +
900–1000 m +
villous +, soft-pubescent +, pilose +, hirsute +  and glabrate +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Disturbed areas, canyons, watercourses +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
campanulate;hemispheric +
sessile +  and petiolate +
alternate +  and opposite +
triangular +
dentate to pinnatifid or palmatifid +  and entire +
3 cm30 mm <br />0.03 m <br /> (?) +
8mm +  and 15mm +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
2-carpellate +
11mm +  and 16.5mm +
2mm;4mm +
persistent +
coroniform +
17 cm170 mm <br />0.17 m <br /> (36 cm360 mm <br />0.36 m <br />) +
0 cm0 mm <br />0 m <br /> (3.3 cm33 mm <br />0.033 m <br />) +
Flowering Aug–Sep. +
13 +  and 16 +
Proc. Amer. Acad. Arts +
bearing subulate enations +, hairy +  and bristly +
hemispheric;convex +
exalbuminous +
Illustrated +
appendaged +  and truncate +
hirsutulous +  and glabrous +
papillate +
Tithonia palmeri +
Tithonia thurberi +
Tithonia +
species +
cylindric +
serrate +  and crenate +
70 cm700 mm <br />0.7 m <br /> (200 cm2,000 mm <br />2 m <br />) +
shrub +  and subshrub +