Small but Important

Croton setiger                                                                                                                            S. Reeve

You have probably seen this plant while hiking, or possibly while driving since it likes to grow in road cuts and disturbed areas. Even if you saw it, you may not have even noticed it since it blends with the landscape and has a really low profile. The plant has the peculiar name of Croton setiger or Dove Weed. This annual grows mainly all through California and into Western Oregon and Washington, and down into Baja. In San Diego, we are at the bottom of its range, as it needs, at minimum, 9 inches of rain a year. This plant grows at low elevations but can be seen up to around 2500 feet above sea level. It can be found in dry soils in CSS, oak woodland, and in grassland habitats. It blooms for a long period of time from spring into fall. Not that you would notice because the flowers are tiny, about an eighth of an inch and they blend into the foliage. The foliage has a lemony chemical smell.

Croton setiger Doveweed                                                                                                  S. Reeve

Why I love it and why I noticed it, is when you get down and look at the flowers they are covered in tiny native pollinators like this blue wasp. This wasp is probably a Spider Wasp or Aporus luxus. This was the best photo I could get with a cell phone. I kind of cut his head off in the picture. What a startling blue! I could have spent all afternoon watching the little pollinators scrambling around on the tiny flowers. It looks like flowers presented on white dinner plates. 

                  Blue wasp (Aporus luxus) on Croton setiger                                                          S. Reeve   

Ron Vanderhoff 

From what I could find the flowers offer pollen in the male flowers presented at the branch tips, and are very accessible to tiny pollinators looking for lunch. Male flowers have no petals but have sepals and stamens. Female flowers are in the axils. The female flowers have no petal or sepals and are just a single swollen ovary with a style sticking up. Not sure how this very unenticing flower gets pollinated? Turns out the beetles probably do it. They are not efficient pollinators, so when they are bumbling around on the male flowers there is plenty of pollen that drops into the female flowers lower down on the plant. Thank you to the Natural History biologists at UCI for the great macro photography, especially to Ron Vanderhoff, so I could understand the flower structure. http://nathistoc.bio.uci.edu/plants/Euphorbiaceae/Croton%20setigerus.htm

                                                                                 

This plant is entirely covered in irritating dense hairs, except for the seeds, and chemically defended against herbivory, but it gives its non-toxic seeds away freely. It is in the Euphorbiaceae and the leaves are toxic and were used as a fish poison to stupefy fish by local Indians. They are a favorite food of birds that forage on the ground like quail and doves. Nutritious seeds are about an eighth of an inch long and can be either speckled or unmottled gray. This may be a reproduction strategy so that some seeds are not recognized as food and go on to germinate. Notice the unmottled seed in the upper left.

J. O'Brien 2007

You can find seed to start this plant. It would seem to me to combine well with spring wildflowers like California poppies and others. The plant forms a low-growing mound less than a foot high and can spread up to 3 feet wide. It is just beautiful to see the neat silvery soft mounds of foliage. I wonder if any nursery has tried to grow this as a retail plant? Anyway, I love it for its silver color, neat habit and popularity with pollinators. Look for it on your next hike.