Helianthus maximiliani Schrad.
CC = 5
CW = 5
MOC = 34
Family - Asteraceae/Heliantheae
Habit - Perennial forb with short, thick, branched rhizomes and somewhat succulent roots, often densely colonial.
Stems - Ascending to erect, to 2 m, moderately to densely pubescent with more or less stiff, short, ascending, often pustular-based hairs throughout, not glaucous.
Leaves - Relatively numerous and well developed along the stem (usually more than 30 nodes), mostly alternate, mostly short-petiolate, often appearing arched. Blades of the stem leaves 4-30 cm long, 0.5-5.5 cm wide, narrowly lanceolate to lanceolate or narrowly elliptic-lanceolate, folded longitudinally along the midvein, tapered at the base, tapered to a sharply pointed tip, the margins entire or less commonly with minute, widely spaced teeth, the surfaces densely roughened-pubescent with minute, usually stout, loosely appressed, pustular-based hairs, usually canescent, also with moderate to dense, sessile, yellow glands, with 1 main vein.
Inflorescence - Solitary terminal heads or small terminal clusters, also usually with axillary single or clustered heads present from the upper leaves, commonly appearing overall spicate or racemose, the heads short- to long-stalked.
Heads - Involucre 12-25 mm long, 15-28 mm in diameter, mostly extending beyond the tips of the disc corollas, the bracts in 2 or 3 subequal series, narrowly lanceolate to nearly linear, tapered to a sharply pointed, slender, loosely ascending to more commonly spreading or recurved tip, the margins with a dense fringe of short hairs, at least toward the base, the surfaces moderately to densely roughened-hairy and often also with scattered, sessile, yellow glands. Receptacle convex, the chaffy bracts 7-11 mm long, narrowly oblong-triangular to nearly linear, angled or short-tapered to a sharply pointed, green, minutely hairy tip, the outer surface also minutely hairy.
Florets - Ray florets 10-25, sterile, the corolla 2.5-4.0 cm long, glabrous but often with scattered, sessile, yellow glands. Disc florets perfect, the corolla 5-7 mm long, yellow throughout. Pappus of 2 scales 3-4 mm long, these oblong-lanceolate, tapered abruptly to a sharply pointed, often minutely awnlike tip.
Fruits - Achenes 3-4 mm long, narrowly wedge-shaped, flattened but more or less 4-angled in cross-section, the surface glabrous, often finely mottled with dark brown and lighter brown patches.
Flowering - July - October
Habitat - Calcareous glades, bluffs, prairies, savannas, fields, railroads, roadsides, and open, disturbed areas.
Origin - Native to the U.S.
Lookalikes - Other species of sunflower, especially H. grosseserratus; more broadly, many other species in the aster family, particularly those in the genera Heliopsis and Silphium.
Other info. - This showy species is found in scattered locations throughout Missouri. Its wider distribution includes a band occupying the central third of the continental U.S. It also occurs outside of this band, especially in the east, but is less common, transient, and possibly introduced in those regions. It can look very similar to the lookalike sawtooth sunflower, but that species has stems which are glabrous and often glaucous. This differentiation is usually very clear, but specimens are occasionally found which seem intermediate and may represent crosses. The arching leaves are also a strong hint to the identity, though sawtooth sunflower often also arches its leaves.
Photographs taken at Shaw Nature Reserve, Franklin County, MO, 9-21-2007, 9-22-2010, and 9-26-2018, Prairie Garden Trust, Callaway County, MO, 9-26-2009, and in Gray Summit, Franklin County, MO, 10-11-2010 (SRTurner).