| 21. | A 2004 Illinois conservation assessment listed " Helianthus silphioides " as critically imperiled within the state.
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| 22. | Lobelias, Helianthus shrumosis ( which is called the woodland sunflower ) and graceful Japanese Kirengeshoma are worth planting.
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| 23. | Native Americans domesticated the wild perennial sunflower " Helianthus tuberosus " by selecting individuals with larger tubers.
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| 24. | "Helianthus arizonensis " is a perennial herb up to 30 cm ( 12 inches ) tall.
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| 25. | "Helianthus carnosus " is a perennial herb up to 60 cm ( 2 feet ) tall.
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| 26. | "Helianthus longifolius " is a perennial herb up to 30 cm ( 1 foot ) tall.
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| 27. | "Helianthus simulans " grows in wet, mucky soils in marshes, ditches, and roadsides.
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| 28. | "Helianthus smithii " grows in wet, mucky soils in marshes, ditches, and roadsides.
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| 29. | There are 82 species of sunflowers ( genus " Helianthus " ), all native to North America.
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| 30. | "Helianthus exilis " is an erect annual reaching heights over a meter ( 40 inches ) ).
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