Longdark Lantern 

The prolonged winter darkness that envelops Serina's poles for months each year, without being followed by the frigid temperatures typical of the season, is a novel circumstance that has never been seen on Serina before the hothouse period of the late Ultimocene. The continued warmth allows plants and animals to remain active in varied ways, even without sunlight. And these factors encourage the evolution of something usually rare in terrestrial organisms: bioluminescence, or natural light that serves many roles in the longdark swamp.  

Plants, animals, and fungi of the polar regions all have evolved the means to produce light in an environment that lacks it in the hothouse. One of the rarest and most beautiful glowing plants is the longdark lantern, a very rare herbaceous plant that grows widely scattered in only a few known regions of the southernmost longdark swamp. This plant - a species of dandelion - is best known for its huge, illuminated flower which is born in the darkest, longest nights of the polar winter, and is visible for wide distances on the forest floor thanks to the production of luciferin, a molecular compound that is shared with most glowing earth life including fireflies and jellyfish. In this plant it is used most obviously for display, drawing in small pollinating birds which find it by its singular showy petal that persists for a fleeting five to seven days before finally fading and wilting away, not returning for many years. The blossom of the longdark lantern can grow to six feet in height, and is born on a short stalk directly out of the dirt. The flower appears greatly derived from its ancestor, with just one canvas-like petal and two pendulous pollen-covered stigmas which must be clung to by pollinating birds in order to reach a nectar reservoir in the hollow tube-like stalk at their base, ensuring fertilization as long as the bird has visited another flower in the same night, carrying pollen between them for distances of several miles. This flower in fact a single floret of incredibly large size; this dandelion belongs to a lineage that has lost the characteristic compound flowers of the daisy family, but which has done so remarkably recently, only 15 million years ago at the start of the hothouse. During the ice age, its ancestors would have been primitive and far more recognizable low-growing flowers, which survived the harsh conditions of the time by changing very little from their earliest relatives.  

An individual longdark lantern produces its blossom very rarely, and more than fifteen years may pass between displays. When the bloom is done, it produces a cluster of hundreds of thousands of tiny, hooked seeds and then relies on chance to disperse them; they readily catch in the fur of a passing animal, and the short flower stalk stalk dries into a woody structure that will stand for as long as two years to make it likely that eventually something will pass by, carrying them miles away from their parent: the luckiest few may find just the right place to germinate, and so go on to produce a flower of their own in many years. In between flowers or before the plant is old enough to grow them, the lantern produces a single immense, complex leaf annually in the spring, with many branching leaflets which grows rapidly to a height in excess of 12 feet and sometimes - though rarely - as high as 25. This leaf serves to store energy from photosynthesis during the 24 hour long days the south pole receives in the summer, and to store it in an expansive underground rhizome. Yet the forest floor, where it grows, never receives very much sunlight, for the tree canopies above gather nearly all that is available before it ever gets so far down. The longdark lantern has evolved over millions of years to cope with the limited energy available to it in a marvelous way, and one which renders even the plant's leaves characteristic and almost as beautiful as its flowers. The inner structures of it chloroplasts, which absorb light to provide energy through photosynthesis, are aligned in neatly stacked formations, forming incredibly thin but dense crystals within the tissues of each cell, and collectively produce a bright, iridescent structural coloration very much like the feathers of many birds. This renders the foliage of the longdark lantern a brilliant, shimmering shade of blue. The rare beauty of a blue plant in a world of green is merely a side effect of a practical purpose: the structure of the chloroplasts intentionally reflect less-useful blue light away, discarding it and allowing more higher-wavelength red and green light to reach the leaves inner surface. The complex crystalized structure of the chloroplasts also serves to slow down light itself as it passes through the leaf, allowing the absolute most of what little it can get to be absorbed before it is lost in the plant's surroundings or on the forest floor. This combination of attributes makes the longdark lantern and its related species among the most efficient photosynthetic plants known, and to survive in places where no other vascular plants can manage, with some smaller relatives even having evolved to survive in certain caves that receive almost no sunlight at all.  

The longdark lantern is not only remarkable for these special light-catching adaptations, or for the sheer size of its bright blossom, but for another novel way of using its bio-light. Most organisms which glow use it as a signal to attract a mate - or a pollinator to serve as a middle man in the process - and the others usually use it to attract a meal. But for plants, one of the most novel ways of using bio-light has been for defense, by attracting a predator to catch and eat a bothersome, plant-eating pest. This fascinating behavior has evolved independently in at least two hothouse plant lineages, including the more common, socially-complex flashlight trees. But the longdark lantern, a solitary plant that grows widely spaced from any of its fellows, is on its own. Its summer leaf growth is not particularly vulnerable to grazers - it is bad-tasting, and can be regrown if it is damaged. But the flower, massive and produced so infrequently, cannot be replaced for many years. When it emerges from the ground, it is highly vulnerable to small forest-dwelling animals that might try to eat it before it opens up and hardens. To defend itself at this time, its sap is strongly bio-luminescent when exposed to air; anything that takes a nibble will cause the wound to flash a bright blue light, usually enough to startle animals from taking another bite. Yet a particularly persistent animal, which still tries to eat the bud, will soon get its face or body all gummed up with the sap; it is sticky, like resin, and clings to plumage or pelage like glue when it dries. It also lights them up like a beacon in the dark, with the light emanating from the dried sap persisting for over 12 hours even when removed from the plant, making them extremely vulnerable to predators and no longer able to hide, and almost ensuring they never get the chance to nibble another blossom again.