Q: Where do sundews (Drosera) live?




Drosera A: There are about seven species of sundews in the USA and Canada, depending on just what you accept as separate species. Most commonly, the list of USA/Canada species consists of the following:

The striking species D. filiformis adds a level of complication to this list. First, there are two well-defined varieties of this species. Drosera filiformis var. filiformis is smaller, is deeply suffused with red, and occurs in the North (and South?) Carolina, northwards to Massachusetts (and Nova Scotia). Drosera filiformis var. tracyi is larger, pale green, and is in the Gulf Coast (Mississippi to Florida and a southwest Georgia).

Some floristic treatments identify D. filiformis var. tracyi as a separate species ("D. tracyi") but this name has not been validly published (it is a "nomen nudem"). Also, the two varieties have very similar seeds and hybridize readily to produce fertile progeny, which is not the case with other North American Drosera.

• D. linearis,
  Montana
• D. intermedia,
  Massachusetts
• D. rotundifolia,
  California
• D. capillaris,
  Mississippi

To add confusion to the D. filiformis distribution, there are a few small populations of this species in the panhandle of Florida which are bright red. It is not clear if these are outlying populations of D. filiformis var. filiformis, or red-variant Drosera filiformis var. tracyi.

Furthermore, you might encounter the names "D. annua" and "D. leucantha", which refer to the pink-flowered and white-flowered versions of D. brevifolia. The current opinion is that these two names do not merit separate species status.

Finally, I think something weird is going on with the populations of D. intermedia and D. capillaris, especially in the Gulf Coast and down into peninsular Florida. In these areas you encounter bizarre " long-leafed D. capillaris" which look completely unlike the D. capillaris you might see further inland. Many people speculate we are seeing hybrid swarms, polyploids or something else similar. I am starting to adopt the heretic possibility that there are some crytic species that have not been properly identified, but I have not spent enough field time to make any kind of final pronouncement. I have some ruminations on this in my 2005 Mississippi/Louisiana field trip report.

By the way, I encourage you to only consider the range maps on this page to be based upon broad---and no doubt inaccurate---generalizations. Habitat destruction also contributes to their inaccuracy. The main function is to give you a general idea of areas that are more likely to have Drosera.

For completeness for US citizens, I included maps of Alaska and Hawai'i. The species in Hawai'i is Drosera anglica, found in the Alaka'i swamp, on Kaua'i.

Page citations: D'Amato, P. 2001 (personal communication); Rice, B.A. 2006a; Schnell, D.E. 1976, 1999b, 2002a; Snyder, I. 2002 (personal communication); personal observation.