Helianthus pauciflorus

Helianthus pauciflorus, called the stiff sunflower, is a North American plant species in the sunflower family. It is widespread across the Great Plains, the Rocky Mountains, and the Great Lakes region, and naturalized in scattered locations in the eastern United States and in much of southern Canada (from Alberta to Nova Scotia).[2]

Stiff sunflower
Scientific classification
Kingdom:
Plantae
(unranked):
Angiosperms
(unranked):
Eudicots
(unranked):
Asterids
Order:
Asterales
Family:
Asteraceae
Tribe:
Heliantheae
Genus:
Helianthus
Species:
H. pauciflorus
Binomial name
Helianthus pauciflorus
Synonyms[1]
  • Harpalium rigidum Cass.
  • Helianthus rigidus (Cass.) Desf.
  • Helianthus subrhomboideus Rydb., syn of subsp. subrhomboideus

Stiff sunflower is a perennial herb 50–200 cm (1 ft 8 in–6 ft 7 in) tall, spreading by means of underground rhizomes. Most of the leaves are attached near the bottom of the stem. One plant can produces 1-10 flower heads, each head with 10-20 yellow ray florets surrounding at least 75 red or (less often) yellow disc florets.[3]

Hybrids between H. pauciflorus and H. tuberosus (Jerusalem artichoke) are known as H. × laetiflorus. The name H. laetiflorus has also been used as a synonym of H. pauciflorus.[4]

Subspecies[1]
  • Helianthus pauciflorus subsp. pauciflorus: 80–200 cm (2 ft 7 in–6 ft 7 in) tall; leaves alternate near the end of the stem, 8–27 cm (3 1⁄4–10 3⁄4 in) long, with tips acuminate (tapered to a point).[3]
  • Helianthus pauciflorus subsp. subrhomboideus (Rydb.) O.Spring & E.E.Schill.:[5][6] 50–120 cm (1 ft 8 in–3 ft 11 in) tall; leaves opposite, 5–12 cm (2–5 in) long, with acute or obtuse tips.[3]

References
  1. "Helianthus pauciflorus". The Global Compositae Checklist (GCC) – via The Plant List.
  2. "Helianthus pauciflorus". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.
  3. Schilling, Edward E. (2006). "Helianthus pauciflorus". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). 21. New York and Oxford – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  4. Schilling, Edward E. (2006). "Helianthus × laetiflorus". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). 21. New York and Oxford – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  5. "Helianthus pauciflorus subsp. subrhomboideus (Rydb.) O.Spring & E.E.Schill". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew.
  6. Spring, Otmar; Schilling, Edward E. (1990). "The origin of Helianthus × multiflorus and H. × laetiflorus (Asteraceae)". Biochemical Systematics and Ecology. 18 (1): 19–23. doi:10.1016/0305-1978(90)90027-D.
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