When exploring the nether I came across an odd item in my inventory with the only description being ‘Nature.’ In my inventory it has a tan and orangish texture, but when dropped on the ground it was not visible, but did display a shadow underneath it. I should note I could not ‘drop’ it from my inventory, but had to click and drag it out. I was also able to pick it back up. 
Upon further investigation I believe it is linked to the grass found in warped forest biomes, as I was able to find more of it when directly breaking the grass block, but not every time. This leads me to believe it is essentially seeds from the nether grass.