In the flood of 1993, areas near Milford Lake and the Republican River were underwater from roughly late July until October. Some species of plants could not tolerate that long submersion and died off. One of these plants was a shrub named wahoo. I don’t know if any of these small trees have returned to the flooded area during the past 26 years.
A totally different species, not a plant but a fungus, the sponge morel, disappeared from some of the lowest lying areas after 1993. The mycelia masses, hair-like structures beneath the soil, did not survive being under water for months.