Ferny Taiwan

Of the 39 fern families identified across the world, 34 can be found in Taiwan. If we look at fern species, some 150 grow in continental Europe, 400 in North America, and 450 in Australia. Taiwan alone, despite covering a total land area of just 36,000 square kilo­meters, boasts as many as 650 recorded fern species. In terms of dens­ity, the island has a rightful claim to the title of Kingdom of Ferns.

First encounters

We arrange to meet Kuo Chen-meng at the Herbarium of National Taiwan University. Kuo holds a PhD in system­atic botany from the University of Zurich. Formerly curator of the NTU Herbarium, he currently serves as honorary president of the Taiwan Ecotourism Association. Versed in all things fern, Kuo always captures people’s imagination when he introduces them to these unfamiliar plants.

How enthusiastic a pteridologist is Kuo? As a student, he noticed ferns growing everywhere in Taiwan but did not know their names. He would skip classes and go into the mountains to collect ferns and make specimens. To provide index cards for his collection, he would consult every relevant book and journal he could lay his hands on, looking carefully for descriptions that matched his specimens and recording their Latin names. During his undergraduate years, Kuo collected more than 500 local fern species and acquired an intim­ate knowledge of the taxonomy of Taiwanese ferns.

In the 1970s the ROC and US governments joined forces to compile Flora of Taiwan, a multivolume publica­tion that contains the most comprehensive inventory of the island’s vascular plants. Kuo’s then-supervisor, Charles E. DeVol, served on the editorial committee, and Kuo himself also contributed his knowledge of Taiwan­ese ferns.

About that time, Kuo received PhD program offers from American, Japanese, and Swiss universities. He eventually chose to go to the University of Zurich to pursue his longstanding interest in ferns. Subsequently he also visited the British Museum, the Berlin Botanic Garden, Leiden University, the National Museum of Natural History in Paris, and the Harvard University Herbaria to explore “type specimens” of ferns—references used when plant species are first named. At the Linnean Society of London, Kuo had the pleasure of seeing specimens dating from 1753.

Kuo tells us about his naming of Cibotium taiwanense. This species of tree fern—common in Taiwan, where it is known as the Taiwan golden dog fur fern—used to be mis­identi­fied as Cibotium cumingii, which is native to the Philippines and Borneo. While studying in the British Museum, Kuo, on a whim, examined all of the Cibotium specimens held there. He discovered that the C. cumingii specimens were in fact very different from the tree ferns in Taiwan. Already knowledgeable about all of the fern families, Kuo did further research into the genus Cibotium and eventually named the endemic species C. taiwanense.

By studying ferns, Kuo Chen-meng has learned to interpret nature’s cycles and see Taiwan from a fresh perspective.

Taiwan is the Kingdom of Ferns. Take a green path and stroll into the mountains—you’ll find yourself surrounded by ferns.

The Jurassic-era flying spider-monkey tree (Cyathea lepifera) and turnip fern (Angiopteris lygodiifolia) are common in Taiwan.

Observing ferns

Ferns neither flower nor produce fruit. Fronds are their major phenotypic trait. One way to identify a fern is to notice its young leaves, most of which are “cir­cin­ate” in shape—rolled up with the tip in the center of a coil, somewhat resembling a question mark.

Researchers distinguish between different ferns by studying the various arrangements and divisions of their leaves: some have bifurcate leaves, others palmate or pinnate. The fact that there’s a special word for fern leaves in English—fronds—suggests how intricate and interesting they are. Upon close scrutiny, we can discern the regular patterns amid the individual variation in the venation of fern leaves, as if we’re looking at geometric figures. Observing ferns confers peace of mind. Far from being pompous displays, these plants exist in serenity.

Kuo Chen-meng recalls a conversation with a psychi­atrist during his time at Zurich. When the doctor asked him how many shades of green ferns had, Kuo realized that the variety was mind-boggling. From a psychological point of view, green environments are the most healing. “We Taiwanese people actually live on the most therapeutic island in the world,” Kuo says.

The orderly arrangements of groups of sporangia on fern fronds are exquisitely beautiful.

Cyclosorus acuminatus

Fishbone fern (Nephrolepis cordifolia)

Evolution and survival

When he speaks of ferns, Kuo always takes the trouble to go back to the genesis of our world. The earth came into being 4.5 billion years ago. Woodlands did not appear until 400 million years ago. Ferns were the most dominant plants at that time, and the forests were made up of tree ferns. Spermatophytes (seed-bearing plants) arrived on the scene 200 million years ago. The first spermatophytes were conifers, which are gymnosperms (plants with exposed seeds), and it was they that replaced ferns as the dominant woodland species. Subsequently, 100 million years ago, flowering plants, which are angiosperms (plants with enclosed seeds), gained preeminence. Since then, broad-leaved angiosperms have dominated our woodlands.

But ferns should not be underestimated. They have been busy surviving in the most unlikely places, such as rocky precipices and broken terrains, where the slightest amount of soil will enable them to live. In dry habitats some ferns preserve moisture by shedding their leaves.

Standing in the walkway outside the NTU Herb­ar­ium, Kuo directs our attention to a tuft of rock-ginger fern (Pseudodrynaria coronans) growing on a tree. “It’s an epiphyte, not a parasite. This means that it has to find ways itself to acquire the moisture and nutrients it needs, which is why the fern encircles the tree trunk. It’s like a roadblock: whatever flows down the outside of the trunk will have to leave behind something valuable for the fern,” Kuo explains with a smile.

Next, turning to a knee-high fern, Bolbitis subcordata, Kuo flips over its fronds and points out the “adventitious buds” at the tips. When the fronds are long enough to touch the ground, these buds will drop onto the soil and grow into new plants. In adverse environments, B. subcordata is able to use this mechanism to relocate to hab­itats that are more hospitable.

Tamariskoid spikemoss (Selaginella tamariscina), on the other hand, copes with drought by changing its face. When the weather is dry, the fronds will curl up, looking withered and dead, only to unfurl again when it rains.

If you wish to learn more about ferns, Kuo recommends beginning with those that grow on trees and rocky surfaces. Relative newcomers in ferns’ evolutionary history, they demonstrate a strong will to survive in hostile environments.

Southern maidenhair fern (Adiantum capillus-veneris)

Ctenitis subglandulosa

Cibotium barometz

Turnip fern (Angiopteris lygodiifolia)

Bird’s nest fern (Asplenium nidus)

Ferny island

Chronologically, ferns across the world can be divided into three groups. The ancient ferns date from 200-400 million years ago. Ferns in the second group have a history of 100-200 million years. The third group came into being no more than 100 million years ago. All of the five families that belong to the first group can be found in Taiwan. Of the 16 families in the second group, Taiwan has 11. And the island also boasts all of the 18 families in the youngest group. We can say that Taiwan encompasses the entire evolutionary history of ferns across the world.

Kuo observes that the island of Taiwan is at once young and old. Geologically speaking, its history is relatively short, but many organisms that inhabit this island can be traced back to primordial times. To explain this paradox, we need to go back to the birth of the island itself. When the island rose at the convergent boundary between the Eurasian and Philippine Sea tectonic plates 2 to 3 million years ago, the earth was experiencing an ice age. Many organisms in the freezing north moved south. As sea levels in the Taiwan Strait fell, areas of the seafloor were exposed, enabling animals and plants to migrate to Taiwan. Like Noah’s Ark, the island provided a refuge for many species, and its complex and varied terrain, rising sharply from sea level to some 4000 meters, came to harbor a wide diversity of ecosystems. It was these factors that gave rise to Taiwan’s great biodiversity.

Overseas experiences, as well as comments made by foreign acquaintances, helped Kuo realize just how special and extraordinary Taiwan is. “At Harvard University, I heard from an ethnobotanist that Taiwan had the greatest variety of millet species in the world.” “At Leiden University, a scholar told me that the Dutch ­regarded Taiwan’s Tsou people as their siblings.” “In Australia, a friend stated that the Austronesian peoples had their origins in Taiwan.”

But it was when Kuo tried to apply the yardstick of the familiar to situations in other countries that he dis­covered that many of the things we all take for granted in Taiwan are in fact very uncommon. While ascending Mt. Kinabalu in Borneo, he expected to encounter conifers at elevations above 3000 meters, but broad-leaved woodlands were all that came into view. Again, this had to do with the ice ages. When the glaciers retreated, conifers ­either ­migrated north or relocated to higher altitudes. “You probably don’t know that the oldest black forest in the world is in Taiwan. When we visit the coniferous forests on Mt. Hehuan, we also come across swathes of Yushan cane [Yushania niitakayamensis]—landscapes to be found only in Taiwan. These plants ‘walked’ from Taichung to Mt. Hehuan.” Kuo also likes to point out that some Jurassic-­era ferns, including the flying spider-­monkey tree (Cyathea lepifera) and the turnip fern (Angio­pteris lygodii­folia), are protected species in other countries but can be found everywhere in the suburbs of Taipei.

By studying the past and present of Taiwanese ferns, Kuo Chen-meng has learned to interpret the cycles of nature and the causal links that connect all things. For Kuo, Taiwan is the Kingdom of Ferns, an island where wounded souls are mended, the place with the greatest ecological diversity that he has seen within such a small area anywhere in the world, a Noah’s Ark from the ice age. Offering an abundance of natural and cultural landscapes, Taiwan is our treasure island.