When I first saw the low-growing bush with yellow pea flowers, I thought it might be an odd form of the evil broom. But how wrong I was! Instead, it is Thermopsis californica, or California goldenbanner.
The leaves are what first clued me in that it isn’t a broom. Though they grow in threes, like French broom leaves do, they are much larger than any broom leaf — some as much as a few inches long. All are covered with soft grayish hairs that make you want to pet them, like the ears of some young animal.
It’s been a while since I looked at a broom flower up close, but at first glance Themopsis blooms appear very similar. Each flower consists of an upflaring top petal, two lip-like lower petals, and a third, bottom-most petal like the keel on a ship. Come to think of it, the overall structure is roughly similar to yesterday’s plant, though the details are quite different. In the pea (or Fabaceae) family, lower petals clasp in around the top of the keel, as if in embrace or protection. You can see this similarity in broom, true lupine, and falselupine, among others. (When it comes to identifying the pea family, keep in mind that the flaglike upper petal can get very large, as you can see in the showy sweetpea).
(note: I originally identified this plant as T. macrophylla instead of T. californica. Thanks to Doreen, below, for correcting me)
One response to “Plant of the day: California goldenbanner”
Marin plants are Thermopsis californica: T. macrophylla, Santa Inez false-lupine is from S. Ca. so, due to a taxon split, ours are not particularly rare .