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Montana Field Guide

Montana Field Guides

Hybrid Prairie Sunflower - Helianthus x laetiflorus

Undetermined Origin

Global Rank: GNA
State Rank: SNA
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:

External Links

State Rank Reason (see State Rank above)
Hybrid between H. tuberosus and H. pauciflorus; reported for Montana.
General Description
Rhizomatous perennials. Stems 100-200 cm tall, erect, slightly hairy. Leaves basal and cauline; mostly opposite; petioles 1–5 cm; blades lanceolate to lance-ovate, 10–25 × 2–8 cm, bases cuneate, margins serrulate to serrate, abaxial faces sparsely hispid, gland-dotted. Heads 3–6. Peduncles 7–14 cm. Involucres hemispheric, 14–18 mm in diameter. Phyllaries 25–35, oblong-lanceolate, 7–12 × 3–3.5 mm (strongly unequal), apices acuminate, abaxial faces usually puberulent, gland-dotted. Paleae (sterile bracts on receptacle) 9–10 mm, entire or 3-toothed (apices reddish). Ray florets 15–20; laminae 25–37 mm. Disc florets 75+; corollas 7–7.5 mm, lobes reddish (at least at tips); anthers dark, appendages dark to yellowish (style branches yellow). Fruit(seldom formed) 4–5 mm, glabrate; pappus of 2 aristate scales 2.5–3.5 mm (adapted from: Schiller, 2006, Fl. North America, Vol. 21).

Flowering in late summer.

Range Comments
Mostly in eastern North America east of Latitude 100 (Kartesz 2009).

Observations in Montana Natural Heritage Program Database
Number of Observations: 2

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Roadsides and fields.

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Citation for data on this website:
Hybrid Prairie Sunflower — Helianthus x laetiflorus.  Montana Field Guide.  .  Retrieved on , from