10 Ginkgo (Ginkgo Genus)

Millenia of Life Renewing

As Dutch elm disease unwound its unstoppable decimation, city foresters began to slowly replace the fallen giants. No longer did great, graceful limbs reach toward one another from across the streets to create shady archways for my own, growing limbs to walk or bicycle beneath as a child. Just as with the Emerald ash borer epidemic, they sought replacements for the destroyed trees, including new cultivars resistant to Dutch Elm disease. These new kids on the block brought along with them hardy dispositions with combinations of pest, salt and sulphur resistance, and a touch of drought tolerance thrown in for good measure.

Subsequently, the boulevard across from my parents’ house acquired several such newcomers along its length. Maples, Northern catalpas, honey locusts, Kentucky coffeetrees and ginkgos began to appear. When my dad discovered two ginkgos planted on the parkway area right in front of their house, he was overjoyed. My enthusiasm for ginkgos arose, most likely, from this contagion of his rubbing off on me, besides the fact that they are truly fascinating. My daughter says the same thing when describing his animated introduction to her of the two ginkgos on the parkway

“I was amazed,” she told me, “to learn from Grandpa that trees can be separately male and female, just like people!”

Frankly, I was equally astonished when I learned this as an adult! Many trees greet us as separately male or female, such as ash, willow, junipers, and mulberries (to name a few). In botany, these are termed dioecious (from Latin, two homes). Other trees do things the monoecious way (L., one home), such as oaks, pines, and birches. Monoecious trees locate their female and male parts on separate branches of the same tree. Things get trickier from here, though. Hermaphrodite trees, such as linden, apple, hackberry and elm trees (to name a few) have both the male and female parts (stamen and pistil) present in the same flower, called bisexual flowers, or perfect flowers. Taking this further, both unisexual and bisexual flowers can be present in combinations on some monoecious trees, and sometimes within the same flower cluster, such as with the Ohio buckeye where the upper flowers are primarily staminate (male) and the lower flowers are primarily perfect (both male & female). Then there is gender swapping, further blurring things in the tree world. For example, the striped maple tree (Acer penslvanicum) changes sex repeatedly, sometimes year to year depending on various factors (age, health, and environmental conditions).

Ginkgos are dioecious. Their separate male and female trees rely on wind to pollinate between them in the spring. This has worked for about 180 million years or more since they first began hanging around the dinosaurs of the Jurassic period. The fossil record shows their leaves have remained structurally unchanged through millennia. Their open veining system is relatively primitive compared to the way deciduous leaves formed in subsequent periods. I’m glad! An eye-catching tree, ginkgos flutter their charming leaves along the branches like little hands, or butterfly wings or fans daintily waving. Two central veins start out from the leaf base going straight up, then fan out in almost parallel lines down to each side of the lower edge with little forking patterns along the way. Most ginkgo leaves have an indent in the center of the fan creating two lobes (biloba).

Ginkgo biloba is the only extant member of its genus, family and order. Researchers studying the fossil record have worked out that their species began to die out during the Pleistocene period’s glaciation occurrence at the time of the Ice Ages. Those who made it (Ginkgo biloba of today) retreated from their rather wide range throughout what is now Asia to remnant forest enclaves in what is now China. Their continued survival was further ensured through cultivation first in China and then, in the 14th century or so, when several thousand trees were introduced to Japan. Lovingly expanding on this, Japanese horticulturists carefully transplanted ginkgos across the nation. Like the revered linden or lime trees of Europe, ginkgos became beloved in their native lands of China, then in Japan, and are now enjoyed in urban streetscapes across the world – including my dad’s boulevard across the street where they invoke delight in any language.

For urban plantings, they are prime candidates, provided they are mixed in with a variety of trees, for these nonnatives provide little more than a branch to land on for our native birds.

Scientists have studied the remarkable immune systems of ginkgos, finding this as the most likely explanation for why this species easily lives to 1,000 years and can even reach 3,000 years old, especially when protected in such areas as monasteries and temple gardens. When juxtaposed against such seeming immortality, I am grateful for their companionship as quiet ambassadors of renewal and ongoing life.

Ginkgos endure, it seems, perhaps not quite so timelessly as the light, air and water that feed them, but do give the effect of coming pretty close! An ancient tree, they developed their reproductive process alongside the conifers and cycads and are classified as gymnosperms (having no proper flowers). Even though ginkgos have leaves, not evergreen needles, they are more like conifers than other deciduous trees because of the way they reproduce. Gymnosperms have ovules presenting themselves to be pollinated. They have no fruit or ovary to protect them like flowers do. Instead, the bare ovule hangs there just like conifer cones do, ready and waiting for the wind to bring male pollen grains over. The ovule (like some conifers) produces a pollination droplet on its tip specifically made for the pollen gametophyte to land on to start the long process of fertilization over the months to come.

When Susan Jane and I arrive at the ginkgo grove, I show her the large male I would like to tag. It overlooks the street, and is not near any walking path, but it does lead to other trees in a coherent sequence for the walking tour.

“Yes, this is a beauty,” she assents, reading the sign before giving it to me to attach. “I see that cone, conifer and deciduous are all used in the text for this. Interesting…because deciduous trees don’t have cones, right?”

“Right,” I reply, “except for ginkgos! Male ginkgos produce pollen cones, and females produce ovules that will become the seeds. When they ripen, they’re apricot colored and fleshy like fruit, but that’s just the seed’s soft outer coating. Female juniper cones look like fruit, too, like round berries but they’re not berries either.”

We step back a moment and look at the rich, green leaves of the male above us. The neighboring tree is female, so we step that way to look for her ‘ovules’ hanging.

“There’s some,” Susan Jane points.

A few round shapes are visible peeking out among the leaves. They are still green and hang in bundles of 2 or 3 on one inch stems.

“Soon these will ripen and fall off the tree to cover the ground. Really pretty among the leaves. At that point, they will be fertile seeds you could plant to get new ginkgo trees!”

“At that point they also stink,” she said.

“Yes, some people do say that” I agreed, smiling. “Especially when that fleshy outer part starts rotting away. Before that, they look pretty tempting to eat!”

“Really!?”

“Yes,” I say, a bit embarrassed to tell my story, but decide to continue. “Last October, my mom and I were walking here collecting leaves. The ginkgo ‘fruits’ intrigued me, not knowing much about them, so I took some home in my pocket and put them in a pretty bowl.”

“Oh no!” Susan Jane says, “your mom has dementia and ate some, right?”

“Yes,” I said ruefully, and tell her the story. “’My mouth is burning’”, I hear my mom say from the other room “‘What could be causing that?’”

“’What?! Did you eat something?’” I call back to her from the living room.

“’I don’t remember!’” my mom says to me. “‘What did I eat?  My mouth and throat are burning.’”

“What, indeed!? Ginkgo biloba seeds are what she ate! While she was busy at the bowl, I was just learning from my resource that ginkgo seeds are not exactly edible. It also informed me that they are foul smelling because they contain butyric acid which gives the fruits their rancid or rotten odor. They didn’t exactly strike me that way, however. The odor from the fruits I picked up was definitely pungent, not terrible, but strong enough that I washed my hands after handling them — which is a good thing to do after collecting them, I read on, because the pulp can cause an allergic skin reaction similar to poison ivy and can be irritating to mucous membranes. Hence, why my mom now felt burning in her mouth and throat. She most certainly must have popped one of those into her mouth. The inner seed inside the flesh is considered mildly toxic, apparently okay to eat (in moderation) but only when cooked. It’s been used forever in Asian cuisine. But you do have to cook it before eating, not eat it raw, because the heat neutralizes the toxins in the seed.”

Susan Jane listens, nodding.

“Wow!”

“Ironically,” I add, “western medicine uses an extract made from the leaves touted as helpful for improving memory and cognition!”

“But what happened with your mom? Was she ok?”

“Oh, in an hour or so the “burning” retreated to only her mouth, and in 2 hours it was only her tongue, the sensation completely gone by bedtime. The next morning there were no aftereffects at all.”

“Good thing!”

“Yes,” I reply.

We continue walking (as it happens over to the red pine next) but I am thoughtful as we depart this life-affirming tree that I so love.

In 1945, Hiroshima’s ginkgo trees were merrily growing when the A-bomb was dropped on the city incinerating everything in its wake, including trees. Growing more or less 1 mile from the epicenter of the blast, one particularly ginkgo tree had its trunk destroyed, but resprouted new leaves from their roots around the base of the trees. These and other tree species very near ground zero that came back from this annihilation became known as survivor trees (hibakujumoku, in Japanese) and are honored today with memorial plaques. They are remarkable symbols, their new buds leafing out every spring in an eternal cycle of growth and renewal. They are ambassadors of enduring hope.

The body is a temporary thing. Eventually, it gets left behind, no longer needed to enjoy the view. When that time comes, we need it only for one last hike up to the mountain top, to climb as high as possible into air the color of azure blue.

My dad’s last breaths took place in the upstairs bedroom of the house that had been his home for 50 plus years. The ginkgos grow on the boulevard just outside where the room overlooks. Their leaves had already turned brilliant yellow weeks earlier, and then chosen their time to create an instant carpet beneath. Maple leaves had also fallen, as had the little-leaf linden’s on the front lawn. I was with him in the room when his eyes opened wide suddenly and looked into mine. His head came up off the pillow. I thought he had something to say, but he didn’t, only looked at me with a wondrous releasing of light from within and out of his eyes exactly like the luminous sky, vast, wide and wholly filled, and into which that light released.

I have found a thing that endures – the wind. It is the same thing as my breath, pulling inside to every capillary crevice oxygen into my heart. And therein lies another abiding thing. Love. Fanned to life with breath and air. Awake, aware, love needs no improvement, no upgrade, no change. It is its own creative life force, sufficient and enough. On immutable wings it floats, simple and free, upon streams of sunlight into everything.

Perched up here on my mind’s imaginary mountain peak, my gaze sinks into the valley below. Pinpricks of light from the houses blink back up at me and into the night sky far away to the horizon. The twinkling lifts across the hills, resembling the look of a million eyes reflecting back the universe of stars above in the glint of a million others.

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