''Helianthus laevigatus'' is a North American species of

sunflower The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...

known by the common name smooth sunflower. It is native to the east-central and southeastern United States from Georgia to Maryland. ''Helianthus laevigatus'' is a perennial herb up to 220 cm (over 7 feet) tall, spreading by means of underground

rhizomes In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

. Most of the leaves are on the stem rather than crowded around the base, each leaf up to 15 cm (6 inches) long. Leaves and stems generally have no hairs, and the undersides of the leaves sometimes appear pale because of a layer of wax on the surface. One plant usually produces 1-6 flower heads. Each head has 5-10 yellow ray florets surrounding 40 or more yellow disc florets. The plant grows soils derived from

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

.Carl S. Keener 1983. Distribution and biohistory of the endemic flora of the mid-Appalachian shale barrens. Botanical Review 49:65-115
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References

External links

Digital Atlas of the Virginia Flora
laevigatus Flora of the Eastern United States Plants described in 1843 {{Heliantheae-stub