Sunflower oil is the non-volatile oil pressed from the seeds of sunflower ("Helianthus annuus"). Native Americans domesticated the wild perennial sunflower "Helianthus tuberosus" by selecting individuals with larger tubers. The sunflower seed is the fruit of the sunflower ("Helianthus annuus"). Sunflower ("Helianthus") is a genus of annual flowering plants native to North America. They grew squash, sunflower ("Helianthus annuus"), sumpweed, goosefoot, knotweed, and maygrass. It is extracted from a seed of a sunflower called "Helianthus annuus". The woodland sunflower is similar to "Helianthus hirsutus", but its stem is rough. There are 82 species of sunflowers (genus "Helianthus"), all native to North America. When threatened it often hides beneath the extended tentacles of the sun anemone ("Stichodactyla helianthus"). Helianthus () is a genus of plants comprising about 70 species. The name is derived from the genus "Helianthus", which is Greek for sun flower. In some species, however, the pappus falls off (for example in "Helianthus"). The larvae feed on developing seeds in flower heads of "Helianthus" species. Wild "Helianthus annuus" is a widely branched annual plant with many flower heads. "Helianthus salicifolius" grows in limestone prairies.