decaying plant is a kind of organic matter
compost is not decayed_organic_matter. dead_grass_leaf is organic_matter. wood is organic_plant_matter. peat is organic_matter. plant_material is organic_matter. compost is decayed_organic_matter. dead_tree is organic_matter. dead_flower is not organic_matter. dead_flower is organic_matter. dead_grass_leaf is not organic_matter.