Helianthus species

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Scientific Name Helianthus annuus USDA PLANTS Symbol HEAN3
Common Name Sunflower, Common Sunflower ITIS Taxonomic Serial No. 36616
Family Asteraceae (Sunflower) SEINet
Reference
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Description Habitat: Plains to montane (3300 to 9000 ft.); dry soils, disturbed areas, fence rows. Widely distributed.
Plant: Erect annual, widely branching 1 to 8 feet tall, rough, hairy stems.
Leaves: Rough, alternate, ovate to ovate-oblong with cordate bases; blades 4 to 16 inches long and nearly as wide on long petioles.
Inflorescence: Bright yellow composite flower heads 3 to 5 inches across with 17 to 30 rays surrounding normally dark brown central disk florets; wide phyllaries ovate to lance-ovate, with ciliate margins, and abruptly narrowed, pointed tips.
Bloom Period: June to October.
References: "Flora of Colorado" by Jennifer Ackerfield, "Wildflowers of the Rocky Mountains" by Carl Schreier and SEINet.
BONAP Distribution Map

Colorado Status:
Native
Scientific Name Helianthus petiolaris USDA PLANTS Symbol HEPE
Common Name Prairie Sunflower ITIS Taxonomic Serial No. 36671
Family Asteraceae (Sunflower) SEINet
Reference
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Description Life zones and habitat: Plains to montane (3300 to 9000 ft.); sunny, dry areas and semi-desert.
Plant: Erect annual 1-1/2 to over 6 feet tall, often-branched stem with fine hairs.
Leaves: Mostly stem leaves, lanceolate to ovate, 1-1/2 to 6 inches long, petiolate, may be dotted with glands, hairy underneath, small teeth along edges.
Inflorescence: Single composite flowers 2 to 3 inches across with 10 to 30 yellow rays and 50 to 100+ reddish disk florets in the center. Resembles Common Sunflower (H. annuus) except for the leaves.
Bloom Period: June to October.
References: "Flora of Colorado" by Jennifer Ackerfield and SEINet.
BONAP Distribution Map

Colorado Status:
Native

© Tom Lebsack 2020