Answer by
FireSurfer (12)
1.Onycha was a sweet spice. === Labdanum is a sweet spice.
2.The Gemara states that only kosher items may be used for the work of Heaven. === Labdanum is a kosher item.
3.The Talmud specifically states that although onycha (shecheleth) is not from a tree, it does grow from the ground and that it is a plant (Kerithoth 6b). === The rockrose bush which produces labdanum is not a tree, it grows from the ground and it is a plant.