カヤツリグサ科ホタルイ属の多年草で、学名は Scirpus wichurae (syn. Scirpus wichurae f. concolor)。英名はありません。
The "Abura-gaya" (Scirpus wichurae) belongs to Cyperaceae (the Sedge family). It is a perennial herb that is native throughout Japan. This herb grows in flatland to montane sunny bogs and can reach 1-1.5 m in height. The stem is triquetrous and the leaves are linear. The corymbs are borne on the stem apices and leaf axils from August to October. The 1-5 spikelets are produced in the corymbs. The fruits ripen in brown, and they are oily glaze and petrolic odor.