Terra 2: A Second Tree Of Life

Tranboo: The Evolution of Tree-like Flora on Terra 2

15 Million Years Post Establishment

A plant species that deserves our undivided attention in this new age is undoubtedly the Tranboo, a species of bamboo native to all of Terra 2. This one species, diverging from the spider bamboo lineage around 7 million years ago (8 million years PE), is the only bamboo found on every landmass, excluding the Tielen Isles, in which bamboo of all kinds is absent. For many millions of years, species such as spider bamboo could only defend against ground dwelling herbivores by either growing above ground roots, lifting the edible plant off the floor to safety, or to form a somewhat symbiotic relationship with the robins that used them to build their nests. These relatively primitive tactics served the first flux of specialized bamboo fairly well, spreading all across Almara where they remain today, albeit in fewer numbers than they were at the end of the Archi Epoch. The large bamboo snails that had preyed on them beforehand had neglected to... y'know... climb the roots. So they inevitably went extinct just over 2 million years ago, not only due to "inaccessible" food but also to a growing population of animals that hunted them. This in turn allowed said spider bamboo to proliferate all over the Almaran Steppe and its various valleys, becoming the 2nd most dominant bamboo species on the continent. However, they were and still are bamboo-like, retaining the limited branching of its ancestor and superficially looking no different at a first glance. But 7 million years ago, before this, a certain group of spider bamboo evolved quite a different strategy to avoid the ravenous bamboo snails. Back when the Great Bamboo Forest was a thing (which it no longer is), the tranboo's earliest ancestors began to use their above ground rhizomes not to hoist themselves into the air, but to instead form a protective sheild around the stalk of the bamboo itself. Interestingly, in the primordial tranboo this was achieved by the stem growing to a fixed size and allowing the growth of the rhizomes to continue indefinitely, causing them to sort of envelope the plant, promptly protecting it from both predators and environmental hazards because of the structural support that these roots provided. Unfortunately, since the stem of the bamboo would stop growing at a fixed age and never grow again (unless it was cut down, in which case it would regrow) it would eventually, over several years, be entirely enveloped by the roots, including the leaves. In a very self-destructive lifespan, photosynthesis would cease as soon as the plant was completely encapsulated, soon dying as a result. But those who evolved past this would become the most successful and most tree-like (in appearance) floral species on Terra 2.

Above; A generalised model of a common tranboo's life cycle from seedling (left) to adult (right). From this, we can observe the still semi-present trait of self-envelopement using the rhizomes, though not to such a degree as its suicidal ancestors.

Modern day tranboo is much more efficient in their life cycle, having both the terrestrial rhizomes and the stem stop growing at a certain size. This prevents the unintentional suicide of their ancestors, allowing modern tranboo to live for a much greater length of time of up to 500 years per individual, with the oldest reaching 7 or 8 centuries at a stretch. Long lifespans can also facilitate greater fecundity as the reproduction cycle of tranboo is unique to them and them alone. Once they reach maturity, after 8 or 9 years of growing, a specimen will produce a set of gametes around the surface of its stem, with no flower needed (ancient bamboo species, including Earth bamboo, used flowers). These gametes then gather, over time, into one single massive sac of sex cells, around a centimeter in length, on the end of the stem called a gamsac, which is carried by the wind to a new location to grow. These gamsacs are produced in high amounts, hundreds being produced each cycle (9 to 11 years). And, due to their quantity coupled with their size, they have a high survival rate of 40%, which, when considering other plants, is amazing. As a result, tranboo forests have spread across the world like wildfire (let us ignore the irony of that statement) and inhabited every continent, growing across the landbridges just before they broke. Being a highly successful species also has its consequences on not so fortunate organisms, such as the spider bamboo. While nowhere near extinct, they have experienced a drastic population decrease ever since the break up in Almara. The past Great Bamboo Forest is no longer a thing, and so the largest concentration of spider bamboo that used to make up this forest has dissapeared, leaving only the populations outside of it i.e the ones in Almara and the Almaran Steppe. However, while multiple species of spider bamboo have gone extinct, the genus as a whole is doing OK for the time being. But now that ice has begun to creep onto the northern shores of Almara, it has begun to weed out week bamboo plants. The only ones left in the far, far north are some miscellaneous species and, most notably, the tranboo. Its rhizome "shell" helps in not only defense from predators but also from the elements such as occasional snowstorms and tornados common to the north. Spider bamboo has no such defense, so from the north they, too, have dissapeared. A major factor that allows some surviving spider bamboo to continue to survive is their relationship with some robin species, which is their only advantage over the tranboo. However, even the tranboo have friends.

Symbiotic relationships on Terra 2 are nothing new, especially not to the bamboo. In Almara there is the robin-bamboo relationship, where flying robin descendants perch in the "nest dent" at the top of the plant and lay their eggs in it. If anything attempts to take down the bamboo plant, such as tall timbara (descendants of the banda), the bird and its partner (if one is present) will swiftly swoop down to the plant's aid in fending off the predator, pecking and scratching the intruder. Over the seas in Okiina and flower a symbiosis between two bamboo species had formed, that being the wormwoods, a binary organism consisting of both a regular bamboo plant as well as a vine-like companion. The wormwoods are still going strong in the connected lands, having become a largely coastal and riverside group as of 15 million years post establishment, specializing further for this symbiosis. The original bamboo has now allowed the partner, the ophids, to not only grow around them but also within them, as it migrates within the stem to take and give nutrients directly. Of the many symbiotic relationships on Terra 2, the tranboo's relationship with certain species of roses has got to be one of the more... dangerous. While not common, only occuring in just 3 species of tranboo, an agreement has been struck between grass and flower in Okiina. Within the rhizome shell, or "trunk" as I will from now on refer to them as, roses may be spotted growing in abundance, weaving in and out of the trunk before occasionally emerging at the top near the tranboo's stems, giving the specimen a flush of colour dependant on the species of rose they partner with. The specific rose group that have bonded with the tranboo, Pen's Roses, have seen a decrease in their flower's size due to their new home within the trunk, as they no longer need to attract pollinating insects, instead allowing their pollen to stick to the bamboo stems. As gamsacs are produced, the hope is that pollen will be caught in their formation and taken alongside it to grow along with the next generation of tranboo. In return for aiding their reproductive cycle, the roses will utilize their still present thorns to protect the tranboo from any would-be grazers such as the therium (a huge, furry capybara descendant not too dissimilar from an ancient ground sloth). Theriums often use their huge front limbs to reach inside cavities in the trunk, which are very common due to the way in which the terrestrial roots of tranboo grow, and rip out chunks of foliage to feed on. However, when faced with the rose thorns that some tranboo now make use of, they are helpless and turn away.

Overall, tranboo is the star floral organism of the Pagomegi Epoch and is a prime first specimen to visit in this time period, showcasing the sheer variety of new and interesting forms bamboo has taken over the past 5 million years since the end of the Archi Epoch. It has and will continue to spread over both landmasses (Okiina and Darsi are technically one landmass). Being the most specialized for cold weather, it seems that the ice age will not be that large of a problem for the tranboo, especially not the recent rose-tranboo hybrids, dubbed "thorny tranboo". But ecological changes are unpredictable, so only time is able to tell whether or not these are a group destined to die or to prosper.