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Plants of ..

Perennial.  

Flower heads are radiate.  

Basal leaves are 

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.Helianthus annuus is among the most variable sunflower species, no doubt due to horticultural breeding.  Flower heads are often extremely large, but can sometimes approach the smaller sizes of several other sunflower species.  The best identifying characters include the abruptly-narrowed, long tips of the involucral bracts, the swollen bases of the disc corollas, the mostly alternate stem leaves (vs. opposite leaves), which are often quite large, broad and ovate, with heart-shaped bases.

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