Plant of the Week
Cliff Jamesia (Jamesia americana)
By Walter Fertig
Jamesia is a genus of just two surviving species of shrubby plants in the Hydrangea family (Hydrangeaceae) that is restricted to the Sierra Nevada and Rocky Mountains from California, Utah, and southern Wyoming to northern Mexico. Paleobotanists have identified fossils dating to the Oligocene (23-33 million years ago) from the Crede fossil beds in southeastern Colorado that apparently belong to an extinct species of Jamesia. Modern Jamesia species can be recognized by their shreddy, gray to reddish-brown bark, large white, or pinkish (often hairy), four or five-petaled flowers, and broadly oval and coarsely-toothed opposite leaves.
Cliff jamesia (Jamesia americana) is by far the most common and variable of the two species. It differs from its cousin, J. tetrapetala (a narrow endemic of scattered Great Basin Mountains of eastern Nevada and western Utah) in having numerous flowers with five petals, instead of solitary blossoms with four petals. Several localized varieties of J. americana are currently recognized, including one that is almost entirely restricted to hanging gardens in Zion National Park and vicinity (the appropriately named var. zionis).
The name Jamesia honors Edwin James, a 19th Century medical doctor and botanist who accompanied explorer Stephen Long’s 1820 expedition to the southern Rocky Mountains of Colorado. Along with two companions, James was the first white explorer to reach the summit of Pike’s Peak (previously reported as unable to be climbed by Zebulon Pike and his Native American guides) and the first botanist to explore and collect alpine tundra habitats in the western United States. During the summer of 1820, James discovered nearly 100 new species for science, including the Blue columbine (Aquilegia coerulea) which would later become the state flower of Colorado.