Arizona Naturalists >>> Sycamore Gallery Flora >>> Asteraceae >>> Tithonia thurberi

Arizona Sunflower

Tithonia thurberi

Arizona Sunflower-weed, Tithonia thurberi, © by Michael Plagens

Found in partial shade on a sandy terrace alongside Madera Canyon, Sta. Rita Mts., Arizona, USA. 10 September 2010.

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Arizona Sunflower-weed, Tithonia thurberi, © by Michael Plagens ANNUAL: Herbaceous annual which may germinate after spring or summer rains. At flowering, plants typically are about 100 cm tall. Branches freely above base of plant yielding a plant half again wide as tall.

FLOWERS: The disc florets are more yellow than Helianthus annuas and the rays are fewer and shorter. Blooming after summer rains, August and September.

LEAVES: Leaves are broadly elyptic/triangular and tapering to tip and base. Margins are round-toothed.

RANGE: Fairly common in the sycamore canyons close to the Arizona-Mexico border.

FRUIT: Each ray and disc flower tops a large seed. Dry single-seeded achene topped by less than a dozen fine bristles.

UNARMED. Without thorns.

The flowers are attractive to a wide variety of insects such as flower buprestids.

Asteraceae -- Sunflower Family

More Information:

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Arizona Naturalist
Sycamore Canyons
The Flora of Arizona's Sycamore Canyons


Copyright Michael J. Plagens, page created 28 September 2013