OC Wildflowers > Broom-Rape Plants > California Broom-Rape
Here is the true story of its first discovery in Orange County.
On 21 July 2005, Kathy Williams & Jennifer Naegele were hiking in Whiting Ranch Wilderness Park (the exact location will remain undescribed). While pausing for the view, Kathy spotted two Broom-Rape plants growing from the hillside near the trail. Jennifer photographed them and the pair kept hiking. Back at the office, Jennifer looked up the plants and ruled out the only two species listed in Roberts 1998. She thought they may be California Broom-Rape, Orobanche californica, but was not certain. She sent some of her photos to Bob Allen. Here are two.
I (Bob) agreed that it was not one of the species presently known from Orange County, California. Using her photographs as a guide, I thought it was Orobanche vallicola or Orobanche californica ssp. jepsonii. In either case, it was a new county record for us.
We agreed to meet on Sunday 24 July 2005 for a field outing to study the plants. Chris Barnhill and I met up with Jennifer, Shawn, and Bobbie Tumolo. The trio had arrived before us and already hiked out to look at the plants. During that foray, Bobbie found two additional plants. They returned to the trailhead, met up with us, and hiked the trail to the plants. Here is Chris Barnhill photographing the original two plants.
Here is one of my (Bob's) close-ups of the flowers. Compare it with Jen's terrific photos (above) and note that in the 3 days between them, several flowers have opened and senesced. The incredible heat and humidity of the last few days probably accelerated its bloom and shortened the lifespan of each flower.
While photographing, I found another plant buried in leaf litter at the edge of the trail, in danger of being trampled. Since it might be trampled anyway, I took this one as a voucher specimen. Shawn, our Geologist, carefully dug it up so we could examine the roots and determine its host plant.
About halfway through Shawn's digging, the soil at the base of the plant, on the uphill side, pushed upward and out popped a large scorpion!
It is a Burrowing Scorpion, Anuroctonus phaiodactylus, a common local species that mostly remains in its burrow and ambushes prey at night. The venom in its stinger will reportedly make you a little naseous, sometimes a little feverish, but is generally of no dire consequence. It rarely stings, preferrring instead to use its large powerful claws to capture insects and spiders. We let it move on down the hillside.
Once the roots of the trailside plant were exposed, we tried to determine if it was parasitizing the adjacent goldenrods (Solidago californica), Coast live oaks (Quercus agrifolia), or grasses. We could not figure out its host. Here is the dug-up plant (at right) placed beside Kathy's original two plants. Note the swollen base of the plant and its horizontal roots. The trailside plant had been completely buried by leaf litter; this explains why it is colorless.
Back at home, I dissected a flower, viewed it under magnification, and keyed it out (with Hickman 1993) as Orobanche vallicola (Jepson) Heckard, although it almost keys out to Orobanche californica.
We returned to the spot the following week in order to trace the roots of another plant found. Sure enough, it was parasitizing the roots of California Goldenrod, Solidago californica (Asteraceae).
Below is a closeup of the broom-rape plant (thick root on right side) and its connection with the goldenrod plant (thin root on left side). The two roots meet near the bottom center of the photo.
Based on its host plant preference, Alison Colwell believes that it is Orobanche californica Chamisso & Schlechtendal - California Broom-rape, possibly Orobanche californica ssp. jepsonii (Munz) Heckard - Jepson's California Broom-rape. Though as she put it, it seems to be a "very, very rare and hard to find" form of it. Specimens were sent to her for morphological study and DNA analysis. Stay tuned!
Unless indicated otherwise, all photos are (c)2005 Bob Allen. Unauthorized use prohibited. Educational use is freely allowed (teaching) as is use by the printed news media (with credit to Bob Allen). Redistribution of the images or information is not allowed without permission.
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