Wandering Spiderweed

It is not only animals that thrive in the longdark swamp. Of course this region abounds in plant life too, most of which grows during the summer months, when the sun never sets near the pole. But some plants have found ways to continue growing through the winter, too. They are parasites. And there are few stranger than the spiderweeds.

Plants of this diverse genus, Arachnodendron, are very unusual parasites notable for their highly specialized leaves which are adapted to be highly thigmotactic - having a sense of touch, and adapted to seek out and wrap around solid surfaces. The flat, strap-like leaves wrap vigorously around anything they come across until they resemble pythons constricting their prey. Then, with sharp hooks at their tips, they penetrate the bark of the forest trees, and once inside, suck out the tree's sugar-rich sap for the plant's own use. With the leaves providing all necessary support and absorbing nutrients, these plants have no roots except for a small initial  root that dies off in their seedling stage. These leaves grow not from their tips but from their bases - a trait common to many grasses - and so as they grow, the plant becomes gradually more distant from where it has grabbed on, descending from one branch like a spider on a silken thread, and coming to another branch, often on an adjacent tree, where it grabs hold again. Once a new branch is gripped by a newly growing leaf, the parasite is able to pull itself upward as it wraps around the support tightly, and so is not limited only to downward movement but rather can crawl slowly through the canopy at all levels, however it needs. 

Many arachnodendrons are vine plants, growing incredibly long stolons that wrap around the branches, held up by long-lived leaves that grow thick and almost woody with age. The large wandering spiderweed though is different in that its stolon dies back over time so that only the most recent 2-4 years of growth is alive at any one time. As each new leaf is unfurled and grasps a new tree, an old leaf gradually browns, dries up, and falls off. In this way the wanderer truly is nomadic, moving its entire body around the jungle at a rate of up to six feet every year. By discarding its aging parts completely as it grows, the wandering spiderweed effectively remains ever-youthful and does not senesce. Provided it does not become damaged by animals or weather or disease, the wanderer is immortal. Some of the very oldest plants may travel up to a mile, one leaf's reach at a time, from where they originated during their lives.

The wandering spiderweed is native to the longdark swamp, and so experiences months of total darkness each year. While most plants go dormant to conserve energy, with trees shedding their leaves completely and even mosses and lichens turning shades of brown, red or gold as they conserve their energy and stop making chlorophyll, this plant never runs out of energy because it can take all it needs from the trees. While it photosynthesizes a little in the summer, becoming a sickly, pale green color, in winter it becomes entirely brown and continues to grow at an unslowed rate, siphoning the stored energy of its hosts to such an extent that small trees may be killed outright by its heavy feeding. The parasite does not care, for by that time it will have grasped the next host and moved on, and so it can be quite destructive - by feeding in this way, it may even be classified as an herbivorous, predatory plant. Spiderweeds use their constant surplus of stolen sugars to bloom at all times of year, light or dark, making them a very important winter food source for varied animals that flock to their large nectar-bearing blossoms and later come to eat the strawberry-like drupe fruits which it produces to spread its sticky seeds. The plant is photosensitive and tracks day length, registering whether it is dark or light and adjusting the pigment in its flowers - which are colored not by petals but bracts (specialized colorful leaves). Summer blooms are red or yellow - bright and easily seen against a green forest background. Winter flowers, produced in the dark, are stark white to stand out from the shadows (and spring and fall flowers are often pink.) 

The seeds of the spiderweed are spread by animals that eat their fruit. Birds eat it if they can, but are not its preferred disperser because they are indiscriminate in where they drop waste. Seedling wandering spiderweeds must sprout on the main trunk of a tree, not out on a small branch, or else a tree is very likely to cut the sap supply and discard its own twigs to rid itself of the baby parasite. Only if the seed is deposited on the main body of the tree, that cannot be severed, can it successfully sprout and grow. Scamps - small arboreal foxtrotters - are the ideal agent to carry these seeds to suitable new homes, for they mark their territories with droppings deposited where a horizontal branch meets the trunk. To try to attract these creatures and keep birds away, the spiderweed has evolved fruit that lacks any bright color, is hidden in the bracts of its flowers, and has a strong scent when ripe that foxtrotters are much better able to pick up than most flying birds, helping to ensure most of its seeds go to the right distributors.