STIFF SUNFLOWER
Helianthus pauciflorus
SUNFLOWER FAMILY (Asteraceae)
Identification
- Flowering time - August, September
- Uncommon in prairies at NW and FF
- Long leafless flower stalks
- Round, flat-topped greenish flower buds
- Leaves much smaller and less numerous on upper stems
This native erect perennial grows up to 8 feet tall with rough, green to reddish stems. Plants arise from underground stems (rhizomes) often forming extensive “colonies” in older, well established prairies. The narrow, stiff, lance-shaped leaves are from 2-8 inches long by 1-2 inches wide and very rough to the touch (H). Lower leaves are opposite with short leaf stalks while leaves on the upper half of the stem are often alternate and much reduced in size (C,D). Long flower stalks bear one to several 2-3 inch flower heads with 10-20 petal-like ray florets surrounding the reddish-purple (A), (sometimes yellow) disk florets (B). Often, round, flat-topped unopened flower buds enclosed by greenish bracts called phyllaries (E,F) are present at the tips of some of the stalks. When the flowers open these bracts persist, lying directly beneath the petals (E,G) and are a helpful identifier. Stiff Sunflower bracts are broad and flat with blunt triangular tips quite different from the narrower phyllaries with pointed tips of many of our other ‘sunflowers’. (For comparison, see Maximilian’s Sunflower photo D)
Found on drier upland prairie sites, flowering in August and September. At Neale Woods a few plants are present in Knull and Hilltop Prairies. At Fontenelle Forest a few rather robust plants can be found in the small open area at the Camp Wakonda trailhead.
Sunflowers with flat or only slightly convex disks (“flatheads”) are often a challenge to identify. There are exceptions but most Stiff Sunflowers have dark disks separating them from all of our “flatheads” but the Common Sunflower (Helianthus annuus). The narrow leaves of Stiff Sunflower are very different from Common Sunflower’s broad, heart-shaped leaves. Occasionally, Stiff Sunflower may have a yellow central disk (photo B) like most of our other perennial sunflowers. Helpful identifiers include Stiff Sunflower’s long, leafless flower stems; the round flat-topped flower buds; the broad blunt-tipped bracts (phyllaries); and its smaller and sparser upper leaves.
The content of NatureSearch is provided by dedicated volunteer Naturalists of Fontenelle Forest who strive to provide the most accurate information available. Contributors of the images retain their copyrights. The point of contact for this page is: Neal Ratzlaff.