- Iowa City3
- Jones3
- Maquoketa River valley and adjacent bluffs, Backbone State Park, north of Dundee3
- Wapsipinicon, south of Anamosa3
- Dubuque2
- Echo Valley, southeast of West Union2
- Johnson2
- Pikes Peak, bluffs along Mississippi River near McGregor2
- Story2
- White Pine Hollow State Forest Preserve just northwest of Luxemburg2
- Winneshiek2
- Along Iowa highway 3 five miles east of Waverly. Along abandoned railroad grade with some small trees1
- Along Wapsipinicon River at US 63, north of Frederika1
- Ames1
- Backbone State Park, Maquoketa River Valley and adjacent bluffs, north of Dundee1
- Backbone State Park, Maquoketa River valley and adjacent bluffs, north of Dundee1
- Butler1
- Cedar Bend Park, 3 miles NW of Waverly, near Cedar River1
- Contact UM Herbarium1
- Echo Valley State Park, east of West Union, Around railroad cut and rock ledges.1