Place
- Canal road west of Houghton1
- Charlevoix5
- Cheboygan7
- Chippewa1
- Clear Creek1
- Clearwater1
- Clinton Twp. 500 ft. N. of Bailey Rd. at N.E. corner of Bailey Rd. and Mt. Tom Rd. 4 mi. W. of Comins.1
- Coconino1
- Colorado10
- Connecticut1
- Contact UM Herbarium167
- Cook2
- Copper Harbor1
- Cuyahoga1
- Dane1
- Defiance1
- Delaware1
- Delta1
- Denali1
- Denver Twp.1