Top grass radical (the cap-form of
艸) — the indexing radical. Anchors
薯 firmly in the edible-plant family with
菜 vegetable,
蒜 garlic,
葱 onion,
茄 eggplant. Here it tags the character as a tuber crop: yams, potatoes, sweet potatoes all grow as
薯, the leafy plant whose value lies underground.
