Roseroot: a rare plant

Leedy’s roseroot (Rhodiola integrifolia subsp. leedyi, Crassulaceae) is a cliff-dwelling succulent listed as threatened under the US Endangered Species Act. For my Master’s, I learned about the ecology and conservation of this amazing subspecies!

The map below shows that the genus Rhodiola in North America is restricted to northern and alpine regions. Leedy’s roseroot is a subspecies of the more widespread R. integrifolia¬†that exists only as disjuncts in New York, Minnesota, and South Dakota–indicated in the black circle on the map. In these non-alpine zones, Leedy’s roseroot persists in relictual populations on moist cliffs. I am one of the only people in the world to have visited every population of Leedy’s roseroot!

Leedy’s roseroot has flowers typical of the succulent family, Crassulaceae, except for that it is dioecious–it has male and female flowers on separate plants. The flowers smell nice and can range from yellow to peach to dark red. The plants are long-lived perennials with crazy thick rhizomes that may act as storage organs in the harsh environments they inhabit.

Minnesota

Notice the blocky limestone. Also notice the binoculars: a crucial cliff-sampling methodology. Photo by John Wiley.

Each disjunct has its own unique qualities. Minnesota is where the subspecies was first documented by John Leedy in the 1940s. This disjunct lies within the Driftless Area, an unglaciated portion of the upper Midwest known to contain other glacial relict species–when the glaciers wiped out the rest of North America, relict populations hung on in the Driftless Area. These cliffs are calcareous, made of blocky dolomitic limestone.

South Dakota

Rapelling, a final crucial way to sample cliffs.

The South Dakota disjunct was recently identified using genetic methods. This population is in the Black Hills region–also an area known for its unique flora. Although the Black Hills are geographically close to the Rockies where the most common subspecies of Rhodiola integrifolia occurs, the Black Hills has a completely unique geologic history compared to the Rockies. This area is dominated by acidic, granite cliffs.

New York

Enjoying Finger Lakes wine at Glenora Wine Cellars. Photo by Don Leopold.

I did the majority of my research on the largest population of Leedy’s roseroot, in the Finger Lakes region of New York. This area is not necessarily well-known for its flora, but it is world-renowned for its wine production! The cliffs along the southern portion of Seneca Lake where Leedy’s roseroot grows are composed of horizontally-plated calcareous shale.


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