Stylisma pickeringii

Stylisma pickeringii (Convolvulaceae), Patterson bindweed or Patterson dawnflower, is an Illinois-endangered perennial prostrate or diffusely spreading herb of dry sand prairies. It is found in the south-central United States. In Illinois, it is found in the sand prairies near the Mississippi and Illinois Rivers in three counties—Cass, Henderson, and Mason. This taxon is represented in Illinois by var. pattersoni.

Images and Distribution:

*Stylisma distribution maps courtesy of PLANTS National Database.

Key Findings:

Three seed colors exist (yellow, tan, maroon).

Vigor differs according to seed color (yellow being the most vigorous, tan the intermediate, maroon the least).

Seed color does not appear to be determined by age.

Seeds are viable for at least two years after storage.

Plants may benefit from occasional ground disturbance.

Seed dormancy is broken by scarification where basal cut, 120-minute sulfuric acid (H₂SO₄) soak, 48-hour sandpaper shake, and 72-hour sand shake all yield high germination (85-100%); sonication and no scarification yield low or no germination (0-2%).

Light is required for initiation of side shoots.

Photoperiod affects development of side shoots.

Cytokinins increase the number of side shoots.

The first side branch originates approximately 7 cm below the soil surface.

Peak flowering is during early July.

Can establish flowering plants in greenhouse.

Scarified seeds can be stored up to at least 8 weeks without affecting germination.

Three rare Illinois insects have been reported visiting the flowers--Heterostylum croceum, H. robustum, and Neorhyncocephalus volaticus.

Eighteen genera of insects visited its flowers during summer 2001.

Apis mellifera and Heterostylum croceum were the two most frequent insects visiting its flowers.

More insect visits occur 10:00-11:00 am than 12:00-1:00 and 3:00-4:00 pm.

More insect visits occur in July than June and August.

Pollen collected from insect bodies resembled that of S. pickeringii.

Plants have been established in the field from seed.

Attempts to propagate via shoot cuttings are in progress.

Students Involved (Eastern Illinois University):

Michelle Barno (2000)

Carrie DuFrain-Butler (1999)

Lynze Greenwood-DeLine (2002)

Chris Heisler (1998-2000)

Angela Kerber (1999-2001)

Courtney LaZier (1998-1999)

Shad Mallady (1999)

Melissa Rycerz (1998-1999)

Martha Sojka (1998-1999)

Brent L. Todd (1999-2002)

Kris VanderMeer (2003-2004)

Brent Waccholder (2002-2003)

Students Involved (University of Illinois):

Ann Claerbout, University of Illinois (2001-2003)

Kevin Donnelly, University of Illinois (2000-2001)

Laura Skoglund, University of Illinois (2001)