Please try our next iteration of the Michigan Flora Online here. Beginning on February 1, 2023, will point to this new site.

The new site offers several benefits over the existing website, including real coordinate mapping, giving a clearer view of the density of documentation as well as more precision about plant distributions and their link to landforms. We will also have the ability to update species pages more regularly, both in terms of new collections and as more existing Michigan specimens are georeferenced. In addition, we have a better photo display, and offer indented keys.


Smooth watery-appearing annuals with translucent stems, often forming dense colonies where abundant seeds have been deposited in a previous season.

The tropical perennial Pilea microphylla (L.) Liebm. was collected in 1958 in the "Nursery between Plant Science Greenhouses and Baker Woodlot" on the Michigan State University campus. Even if not actually planted there, it surely cannot overwinter, and is thus not considered an element of the flora. 

1. Mature achenes mostly 1.1–1.4 mm wide, deep purple- or olive-black with narrow pale margins, warty on the sides with low irregular raised bumps.

P. fontana

1. Mature achenes 0.7–1 (–1.1) mm wide, pale yellowish or greenish to light brown, often marked with darker ± elongate but scarcely raised speckles.

P. pumila

All species found in Pilea

Pilea fontanaBOG CLEARWEED 
Pilea pumilaCLEARWEED 


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. February 1, 2023.