''Helianthus silphioides'' 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 names rosinweed sunflower or Ozark sunflower. It is native to the central United States, primarily in the
Ozarks
The Ozarks, also known as the Ozark Mountains, Ozark Highlands or Ozark Plateau, is a physiographic region in the U.S. states of Missouri, Arkansas, Oklahoma and the extreme southeastern corner of Kansas. The Ozarks cover a significant port ...
and the
Tennessee Valley
The Tennessee Valley is the drainage basin of the Tennessee River and is largely within the U.S. state of Tennessee. It stretches from southwest Kentucky to north Alabama and from northeast Mississippi to the mountains of Virginia and North Car ...
with additional populations north into
Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...
and
Illinois
Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...
and south as far as
Louisiana
Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...
,
Mississippi
Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...
and
Alabama
(We dare defend our rights)
, anthem = "Alabama (state song), Alabama"
, image_map = Alabama in United States.svg
, seat = Montgomery, Alabama, Montgomery
, LargestCity = Huntsville, Alabama, Huntsville
, LargestCounty = Baldwin County, Al ...
.
''Helianthus silphioides'' grows in open locations. It is an perennial herb up to 300 cm (10 feet) tall. Leaves are broadly egg-shaped. One plant usually produces 3-15
flower head
A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...
s, each containing 8–13 yellow
ray florets
The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...
surrounding 75 or more red
disc floret
The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...
s.
A 2004 Illinois conservation assessment listed ''Helianthus silphioides'' as critically imperiled within the state. The species is also considered endangered within Kentucky, likely due to habitat loss of open oak woodlands and barrens. Throughout the remained of its range, it is considered apparently secure or conservation status is unknown.
[Molano-Flores 2004]
References
External links
Photo of herbarium specimen at Missouri Botanical Garden, collected in Missouri in 1992Ozark Edge Wildflowers
silphioides
Flora of the United States
Plants described in 1841
{{Heliantheae-stub