Sunflower

sunflower Helianthus annuus, an annual plant of the daisy (Asteraceae) family, grown mainly for the valuable oil obtained from the seeds. These typically contain 35–45 per cent by weight of oil; they are also a popular and nutritious snack food, raw or roasted and salted.

The sunflower is remarkable for its height (up to 3.5 m/12') and the size of its flower heads (the record is a diameter of 75 cm/30"). A flower head may contain several hundred (or even up to 2,000) seeds. The name sunflower (and the generic name Helianthus, which means the same) is probably derived from the resemblance of the yellow flower head to the sun; but it may have to do with the plant’s habit of keeping its maturing flower head turned towards the sun, so that it faces east at dawn and west at dusk. The French name tournesol suggests this, as do the Italian, Spanish, and Chinese names.