Chokeweed

Chokeweeds are several related species of parasitic grass that prey on other plants, often trees but sometimes plains grasses, found across Serina in the Pangeacene in almost all environments except extreme alpine and desert, but particularly within the tropics. Their form is highly derived into a long, curling vine with leaves modified into twining, wire-like tendrils up to five feet in length that search out nearby plant stems and, when they find one, curl around it with great tenacity until the neighboring stalk is firmly held and the weeds' own stem is pulled into physical contact with that of its victim. As soon as a hold is established, it produces roots from the node from which the tendril originated which burrow into the stem of the captured plant and once there branch out into numerous, minute threads which spread like fungal bodies through its tissues and thread between individual cells, piercing their cell walls and hijacking their supply of both moisture and nourishment for its own use. Once the chokeweed has established itself in one stem, it immediately begins searching for another, putting out a new tendril, pulling itself a little higher off the ground, and going onward until a very old plant may stretch for hundreds of feet up through the jungle canopy. Stems may break off an established plant to no ill effect, so long as the severed portion has its own roots, and the lower portion will quickly produce a new leading shoot. Chokeweed never roots into the soil, and the production of roots is directly related to the presence of growth hormones detected in other living plants.

Chokeweeds vary from semi-photosynthetic to totally parasitic. Though a handful of species can produce a small part of their own energy needs from the sun, most are entirely reliant on stealing nourishment from other plants and most species - lacking green chlorophyll - are colored brightly in shades of yellow, red, and purple. Because of this, chokeweeds are easily spotted among the leaves of their host plants and often quite beautiful. Their effects on the plants they victimize, however, are less so. Large trees may consider the chokeweed only a nuisance, but seedlings - even sapling several years old - can be so heavily attacked that they are starved of nutrients and die under a mass of the parasite. Chokeweeds are unusual in that they are largely left alone by symbiotic ants which normally aggressively remove competitive plants from their host trees. This is because, by parasitizing the tree and taking up its nutrients, they also take in their growth hormones and thus their distinctive scent, which the ants utilize to recognize their hosts. Even though the parasite looks nothing like the host, the ants identify it as their own. So left alone, it can spread densely through the forest in thick tangles.

To reproduce, chokeweed has taken to using animal carriers, one of only a few grasses to do so; ancestral grasses were wind-pollinated, but wind is absent in the jungle where many chokeweeds live, and so most chokeweeds have had to adapt to using animal pollinators. Their flowers are remarkably large and colorful for a grass, likely because as a parasite the chokeweed doesn't need to worry about wasting any of its hard-earned resources. Its flowers are thus extremely showy, fragrant, and born in dangling, pendulous bundles - as long as six feet in some jungle species - that descend down from the canopy, where they attract a variety of pollinators including not only the ants that guard the tree but vespers, beetles, birds and even tribbats. Once fertilized, each blossom produces a small, berry-like pod which contains hundreds of tiny seeds. The seeds are buried in a thick, sticky flesh relished by all sorts of animals, from birds to tribbetheres and many sorts of insects, which pass them in their droppings when they eat the fruit whole and also get the seeds stuck to their beaks, paws, legs and mouthparts, where they are likely to eventually rub off on a branch as the animal moves on after feeding. Whether a seed lands on a new plant stem in a birds' droppings or on a tribbat's hand doesn't matter much to the chokeweed, so long as it reaches another host. Only here will it germinate, injecting its first root into the tissue of an established vascular plant and therefore starting its life as a full-fledged parasite independent of the ground. If a seed falls to the ground, it will never germinate, or if it did, would quickly starve to death.

Most chokeweeds are generalists and not specific to a single host species, though species do generally grow either in trees or on the ground, victimizing other grasses, and differ in the form of their flower stems (the former growing downward in hanging bunches, the latter up above the grass on thick stalks.)

above: a red-colored chokeweed on a sunflower tree.