Flora of the Southeastern United States
2022 Edition

Colors

Data mode

Key to Helianthus, Key C: perennial sunflowers with leafy stems and red disk flowers

1 Stems glabrous or glabrate and often glaucous; leaf margins not revolute.
..2 Plant 4-7 dm tall; blades of ray flowers 8-9 mm long; leaf blades 3-7.5 cm long
..2 Plant 15-25 or more dm tall; blades of ray flowers 28-35 mm long; leaf blades 8-21 cm long
1 Stems pubescent, not glaucous; leaf margins revolute or not.
....3 Leaf blades long and narrow, linear or lanceolate and usually > 10× as long as wide.
......4 Plants < 1.5 m tall; leaves < 1 cm wide; rhizomes lacking or poorly developed
......4 Plants > 1.5 m tall; leaves > 1 cm wide; rhizomes well developed
....3 Leaf blades shorter and broader, lanceolate, lance-ovate, deltoid, deltoid-ovate and usually < 5× as long as wide.
........5 Phyllaries 1.5-3 mm broad, lanceolate
........5 Phyllaries 3-5 mm broad, oblong, ovate, or obovate.
..........6 Abaxial surfaces of leaves and ligules lacking subsessile glandular trichomes; leaves usually broadly ovate to orbicular and with a petiole > 1 cm long
..........6 Abaxial surfaces of leaves and ligules with subsessile glandular trichomes; leaves usually lanceolate to lance-ovate or rhombic-ovate and with a petiole usually < 1 cm long.
............7 Phyllaries oblong-lanceolate, apex acuminate, abaxially usually pubescent
............7 Phyllaries elliptical to oblong-ovate, apex acute, abaxially glabrate.
..............8 Plants 8-20 dm tall; upper leaves usually alternate; leaf blades oblong-lanceolate to lance-ovate, 8-27 cm long, acuminate at tip
..............8 Plants 5-12 dm tall; leaves opposite; leaf blades rhombic-ovate to lance-linear, 5-12 cm long, acute or obtuse at tip