A seedling sunflower's stem, or stalk, is made up of the Epicotyl, which is just above the first leaves (the cotyledons) of the plant, and the hypocotyl, which is below. The woody mature stems are sturdy, round, and often branch out to hold additional blooms depending on the sunflower variety.
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Bobbie Brewer has been writing since 1990, with work appearing in print and online. She covers topics related to international travel, outdoor recreation, parenting and gardening. Brewer holds a Bachelor of Arts in English from California State University, Sacramento.