The Dawn Muricene woodlouse-grasses have extant descendants outside the still quite species-poor palm-grasses. This much more diverse group of isopod symbiotes is collectively known as the skystalks, though only a few of its members reach the immense sizes that give the lineage its name. The current world record holder for tallest (though not largest by mass) plant is Bouteloua altifolia. Its thin, towering stems reach up to seven meters in height. It is not, however, tree-like in any capacity; it's simply a massive, over-elongated culm with regular-looking leaves, seeds, and stems.
This structure is shared generally across all skystalks; smaller forms are nearly indistinguishable from the stems of average turfgrasses, while mid-sized species are a key component of tall prairie-grass communities across most of Panapterra. All of them are quite devoted to their crustacean friends; some varieties produce nectar only within their hollow stems, preventing any species besides their mutualists from taking advantage of the free food source. Others make use of well-armored isopods, a subspecies of A. arborealis, to fend off mosquitoes looking for a snack.
Their diversity is highest in the Loxodian tropics where all woodlouse-grasses originated. Here, giant skystalks loom high above their neighbors. They don't form a canopy or overshadow lower-level plants, for they're too skinny to cast much of a shadow. They are also quite short-lived; such a massive herbaceous stem cannot stand for long, and they generally collapse during their first major rainstorm. They then send up an inflorescence carrying hundreds of tiny florets. The stalks expend all their remaining energy in this endeavor, dying as soon as their seeds have matured. The largest species have the shortest lifespans, growing to full size in under a month and rarely living more than another sixty days. Smaller skystalks may persist for up to 18 months, but all are limited by the fact that they have entirely foregone rhizomes and other forms of vegetative reproduction. They exist only as singular stems, standing alone amidst the masses of other plant species. While this limits them to short lives and low densities, it allows them to put all their energy into seed production, bolstering their population sizes and leading to their high levels of genetic diversity. Indeed, their ability to mutate quickly is key to their survival. As grazing isopods gradually become more resistant to their toxins, they must constantly innovate and adapt new ways of repelling their enemies.
They are also a vital component of secondary succession; like the basket-grasses, they are fast-growing and colonize disturbed areas almost immediately after a disaster occurs. They are often found growing in the gaps between baskets, forming a temporary community for a few months following a wildfire. With time, rat-grasses will fill in the lower layers. Palm-grasses may even begin to sprout after a year or so, their leaves growing higher with each subsequent spring. The basket-grasses will soon find themselves outcompeted, but the skystalks continue to grow even when the climax community has taken over. When the second generation of seeds sprout, they will shoot up above the forming canopy, waving in the wind that blows across the young pseudoforest.