蝦夷方言藻汐草

Sum “west” with kur “person” explains the shorter recorded form. Fukasawa compares sumkur with the expanded sumunkur; the NINJAL edition directly attests sum un kur for a person in western Hokkaido. Its two corpus entries repeat one expression. The expansion adds material absent from シユムグル, so sumkur is retained with that comparison. Tamura’s west is regionally oriented toward Usu and Abuta, and the homonym sum “oil/fat” supplies no evidence for this group name.