When we walk past a tree, if we notice it at all, it is only to
name it, then move on.
”
There is a sycamore,
”
we say, and the experience is over.
When we walk past a tree, if we notice it at all, it is only to name it, then move on. “There is a sycamore,” we say, and the experience is over.
I am not the most careful observer, but over the years the California Buckeye has demanded a closer look and begged additional questions. Why do those beautiful clusters of white flowers at the end of each branch produce hundreds of blossoms in the spring but only one or two large chestnut-like seeds? In most plants, each individual flower produces at least one, often many seeds. When the flowers fall and the seeds ripen, why isn’t each Buckeye branch drooping under the weight of hundreds of seeds?
Why does the California Buckeye lose its leaves in August? I thought deciduous trees dropped their leaves in the fall as winter was approaching, not in the middle of summer.
Out West, we have so few native trees with a showy spring bloom that the California Buckeye’s blossom clusters are very conspicuous, especially when the trees are in dense stands. By now, in drier locations, the Buckeye’s flower clusters have begun to dry up. But crossing Hecker Pass this past weekend, I saw many still-lush trees that prodded me to finally seek answers.
I discovered that in each large cluster of flowers, most of the flowers have male parts only – “stamens that produce the pollen to fertilize the female parts.” Only on the very tip of the clusters are there some flowers that have both male and female parts where seeds can be produced.
When ripe, the Buckeye’s polished golf ball-sized seeds are wrapped in a pear-shaped leathery case that hangs from the end of the branch. Only one or two of those cases is produced per branch. Why weren’t more seeds produced by the other flowers with female parts? There should be more than just one or two seed cases. Apparently, many of those flowers do produce seeds, but as those other seeds begin to ripen, the tree will spontaneously abort the excess ones leaving only one or two. In this way, each of those large and beautiful clusters produces just one or two seeds.
All plants pull water, lots of water, up from their roots and out the leaves as water vapor. According to Rutherford Platt in “This Green World,” “a single corn stalk will lift 440 pounds of water during its brief growing season” which would put a cornfield under a five-foot lake if the season’s water were collected. Knowing that, imagine how much water a Buckeye tree needs – hundreds of gallons a day.
Plants that grow where water is scarce, as it is during the California summer, possess strategies for conserving water. Having tough, leathery leaves or pointing only the edge of the leaf toward the sun are a couple methods plants use for slowing water loss. Since it is the leaves that demand the water, the Buckeye conserves water by dropping them in midsummer when the demand exceeds the supply. When the leaves are gone, the tree goes dormant until spring, ending any further water needs.
A final curiosity. Each source I consulted about this tree made the seemingly contradictory point; the fruit of the Buckeye is poisonous, and it was a food source for the Native Americans. In years when the acorn harvest was poor, the Buckeye seeds were a substitute food source that were roasted and eaten after up to 12 hours of leaching the toxins with water.
The Indians also used the toxic Buckeye seeds to catch fish. They would crush Buckeye seeds and throw the meal into a stream. Stunned and disabled, the fish would float to the surface to be easily plucked by the Indians.
But the Buckeye’s best feature is its beauty. Leafing out in February, blooming in May or in its winter nakedness, the distinctive low, broad dome of the California Buckeye is a lovely sight on our hills.
