Seedrians is a fan term for a species of plant-like aliens who have evolved to assume sentience and more animalistic forms that appear in the Sonic X series
Aparence
Male Seedrians, referred to by the fans as Thorndrigans, are slightly larger than most of the inhabitants of Sonic's world, and are usually rather round, with short tails, small antler-like growths on their heads, and a colored ridge on the top of their heads; they are largely similar to trees in their make-up. Female Seedrians, or Petali, more closely resemble their plant ancestors, being mostly slender and having an arrangement of petals sprouting from their waists and buds--or bloomed flowers--atop their heads.