Life

The Loneliest Tree in the World: The Wood Cycad and Its Quest for a Mate

If common individuals were tasked with enumerating 10 species teetering on the precipice of extinction or having succumbed to it, then those 10 species would likely comprise the fauna most akin to Homo sapiens, with scarcely any representation from the botanical realm. However, there exists a tree bearing the epithet “the forlorn of all” as its calling card, captivating human attention and instilling in them a fervent desire to procure a companion for it and propagate its progeny.

On a fateful day in 1895, the British botanist John Medley Wood stumbled upon this tree during a stroll through the Zululannoye Forest in southern Africa. It stood incongruously on a precipitous incline at the forest’s edge, out of harmony with its surroundings. Its trunk, so stout as to resemble a palm tree when viewed from above, defied classification as either a palm or any other common arboreal specimen.

At that juncture, Wood plucked numerous suckers from the vicinity of the tree and dispatched one to the esteemed Kew Gardens in London. Subsequently, the tree was christened Wood Cycad, in honor of its discoverer, and categorized as a member of the cycadaceous family. Unexpectedly, over a century has elapsed, yet humanity has failed to uncover another Wood Cycad.

Although the initial impression of the tree suggested a sizable quartet, those four trees were, in actuality, a singular entity. They constituted clones of the principal tree, their genetic makeup nearly identical to that of the maternal tree, having undergone asexual reproduction. Wood cycads are dioecious plants, necessitating a partner to perpetuate their lineage. However, the solitary extant wood cycad in the world is male.

Under propitious environmental conditions, male cycads will bloom resplendent orange-yellow cylindrical “male cones” annually during a predetermined season, measuring 20 to 40 cm in length. These structures, also known as microsporophylls, coexist alongside “female cones” borne by female plants. Termed megasporophylls, these structures are spherical in shape, exuding a lustrous sheen. Regrettably, despite the tree’s repeated blossoming and abundant pollen production, it never garners a response to the “billets-doux” it dispatches, nor does it ever give rise to seeds.

According to records, cycad fossils dating back to the Permian period, some 280 million years ago, have been discovered. During that era, cycads proliferated worldwide, reigning supreme alongside dinosaurs. However, the leaves of nearly all extant cycads harbor the highly toxic cycadin toxin. Scientists posit that cycads evolved to possess poisonous foliage early on to safeguard themselves against gargantuan herbivores. Digestive tracts of certain dinosaur fossils have contained ingested cycad seeds, which retain relatively intact seed coats, providing evidence that these seeds were ingested whole, rather than being reduced to fragments through mastication. One can surmise that cycads and other plants employed this mechanism not only to avert dinosaur poisoning but also to facilitate the perpetuation of their lineage and the proliferation of their foliage.

Yet, despite surviving several mass extinctions, cycads eventually experienced a decline. They possess numerous inherent deficiencies, such as protracted growth cycles, exacting environmental requirements, large and unwieldy seeds, and an abysmally low germination rate. The adage, “the iron tree blooms only once in a thousand years,” may not be entirely accurate, but it aptly encapsulates the arduousness of the cycad’s flowering.

Presently, a meager 300 cycads remain in the world, with the prospects for most of them appearing bleak, teetering on the precipice of imminent extinction. Analogous to their cycadaceous counterparts, the Wood Cycad cannot evade its destiny. Although more than 500 Wood Cycads exist globally, these plants essentially amount to the same male tree. Biologist Richard Foddy poignantly described it as “the most solitary creature on the planet.” Given the cycad’s extraordinary longevity, the Wood Cycad unequivocally epitomizes the phrase “the most solitary creature in history.” A malevolent curse—endure an extended lifespan and perish in isolation.

At present, botanists persist in their quest for a female Wood Cycad, yet their search remains futile. What course of action should they pursue? In this regard, scientists have devised a solution—to facilitate cross-species mating and aid in locating a mate for the tree.

In Africa, a closely related cycad known as Nelta cycad coexists with the wood cycad. By employing “backcross breeding,” botanists have successfully interbred the Wood Cycad and Nelta Cycad, resulting in a profusion of female offspring. These progeny are subsequently crossbred with the lone male Wood Cycad. In theory, the resultant female plants will closely resemble the desiredspecies that humans seek to obtain. However, in practice, this process is exceedingly protracted. After all, it would require more than a decade to complete a single generation of cycads. Adding to the sense of helplessness is the realization that the “Wood Cycad” cultivated through this method merely approximates the Wood Cycad, without achieving purity. Unless the elusive female Wood Cycad in some corner of South Africa deigns to reveal herself, the quest persists.

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