I've got vallisneria tortifolia... or spiralis, I can't really tell, the two are almost the same. Tortifolia grows much shorter though. Mine has maxed out at about 18" so far. However, I think it could be spiralis; I have to wait and see if the leaves will grow any longer. The old leaves it had were thin and staight-ish when I first got it. After I planted it its new leaves and its runner's leaves are all heavily spiraled and thick. I can get some at my LFS for 99cents a plant and I can charge you for nothing but the shipping costs and reparations. *and taxes from the store.