Bartonia virginica (L.) Britton, Sterns & Poggenb.
Common Name: SCREW-STEM
Coefficient of Conservatism: 7
Coefficient of Wetness: -3
Wetness Index: FACW
Physiognomy: Nt A-Forb

Bartonia virginica on granite pavement A. A. Reznicek on granite pavement

Moist sandy ditches, shores, and hollows (including borrow pits); depressions in forests (of oak, etc.); moist mixed forests, mossy swamps (hardwoods, tamarack); often with a thin layer of Sphagnum or Polytrichum; occasionally in drier ground.

Plants vary in stature from as short as 5 cm, with a single terminal flower, to as tall as 30 or even 40 cm, with as many as 40–50 flowers in a narrow compound cyme. Rarely a depauperate individual in a population may have all the leaves alternate, but such plants can be distinguished from B. paniculata by their slightly larger anthers and capsules dehiscing only below the obscure style. This plant has a distinctive greenish yellow color when fresh, while B. paniculata is often more purplish.


Alcona County
Allegan County
Barry County
Bay County
Benzie County
Berrien County
Calhoun County
Cass County
Chippewa County
Clare County
Clinton County
Crawford County
Gladwin County
Grand Traverse County
Gratiot County
Ingham County
Ionia County
Jackson County
Kalamazoo County
Kent County
Leelanau County
Macomb County
Mason County
Midland County
Monroe County
Montcalm County
Newaygo County
Oakland County
Otsego County
Ottawa County
Presque Isle County
Saginaw County
Schoolcraft County
St. Clair County
St. Joseph County
Van Buren County
Washtenaw County
Wayne County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. May 16, 2022.