I clearly remember a college field trip to a rolling grassland not far from my university. We had come at exactly the right week in late May and found a good dozen species of pink orchids of the genus xe “Orchis” Orchis in the south-facing sward. Then we walked up the meadow toward the vast Palatinate Forest, which runs all the way to the border with France, and there in the half-shade of the beeches along the forest edge were the delicate orchids called “little white forest birds.” Going deeper into the Palatinate, we found swamp orchids by a creek and in dark patches of woodland, brown orchids with none of the chlorophyll that gives most plants their greenness. This variety, called the “bird’s-nest orchid,” lives off the nutrients it receives from a symbiotic fungus.

No other plant family held quite the same fascination for me as orchids did, maybe because of their relative rareness in northern Europe and certainly because of their unusual appearance – their delicate shapes and configuration, the deep spurs that hide their nectar. They weren’t structured like any other flowers, and they seemed somehow special in a mysterious way.

As the radius of my wanderings expanded, I had the opportunity to see some amazing orchid habitats across Europe. On a backpacking trip into the Swiss Alps, I saw orchids in abundance for the first time. I was astonished at the profusion of their blooms across the high mountain meadows, their pink spikes glowing amid dozens of other summer flowers and all of it back-dropped by snow-capped peaks. It was breathtaking. There were at least a dozen species in those meadows, including the pyramid orchid that Charles Darwin had studied and written about. An orchid enthusiast himself, Darwin gathered wild orchids near his home in Kent and propagated them. In fact, orchids inspired some of his most critical thinking on natural selection. In his book, “The Various Contrivances by Which Orchids Are Fertilised by Insects,” he explains the co-evolution of insects and orchids and calls them “amongst the most singular and most modified forms in the vegetable kingdom.”

I shared Darwin’s enthusiasm for these “singular” creatures, and on hikes I took into the Pyrenees, southern Italy and Greece, I discovered a whole new realm of orchid species that I had not seen before. Some of them were oddly shaped, mimicking bees and other insects, while others grew to amazing sizes and had a sweet, honeyed scent.

In graduate school on botanical research expeditions in the tropics of Asia, Africa and Panama, I began to realize how narrow the European range of orchids was. Tropical orchids seemed nothing like the ground-based European varieties I had known. Almost all orchid species in the warm rain forests lived as epiphytes, growing from other plants often high up in the canopy. The shapes, colors and, in many cases, the scents were out of this world. Their diversity seemed endless; hardly ever would I find two individuals of the same species.

My experience with orchids mirrors the global patterns of orchid distribution. While temperate areas tend to have fewer species and predominantly terrestrial ones, tropical orchids are much more diverse and most are epiphytic. Central Europe has about 250 species of orchids, yet Panama, barely one-tenth the size, has more than 1,300 known species, with many newly discovered ones being reported every year.

That’s typical of the difference between tropical and temperate places worldwide, and the explanation for this lies deep in the Earth’s past, in its geology and weather patterns.Issue
No. 16, 2012