Sometimes “it takes a village” just to identify a plant. I had been struggling with this one since last summer after I photographed a perfect little native bee sampling it in the Capitol Forest. I was so intent on capturing the bee, I completely forgot to photograph the rest of the plant or take a sample.
Last week I finally sent the photo to a friend who doggedly pursued an identification. Based on where it was growing—disturbed areas along dry, sunny roadsides—we believed the plant was probably an introduced species. Sure enough, when the mystery was solved, our theory held.
The plant, Centaurium erythraea of the Gentian family, is native to Europe, parts of northern Africa, and western Asia. But due to its popularity as a medicinal herb, it has spread across the globe. In North America it has naturalized on the east coast from the Province of Québec to Georgia, and on the west coast from British Columbia to California. It is also common in Australia.
Commonly known as European centaury or common centaury, the plant is a biennial herb with a basal rosette of leaves and opposite triangular leaves along the main stem, non of which you can see from my photo. In Europe, the herb is used as a tea and thought to help with digestive problems.
I found no information on the composition of nectar or pollen, but the little native bee in the photo is loaded with brilliant yellow pollen. Several of these bees were working the flowers at the time I took the photos in July and they certainly seemed happy with their find. In Europe the plant is known to be visited by hoverflies, bees, moths, and butterflies (Brys and Jacquemyn 2011) but it can self-pollinate with good results as well (Ubsdell 1979).
Thank you mbee for solving the puzzle.
I just wanted to say how much I enjoy your articles. I love the wide range of topics you cover. They’re always well written and very interesting. I share them with our bee club from time to time and some of our members have subscribed to your site. Nice work!
President, San Francisco Beekeeping Association
Thanks, Charlie! Much appreciated.