Having the capability of moving in the sea by using two flagellums, the spore of kelp (the size is about five micrometers) is especially called 'zoospore.'
コンブの胞子（大きさは5マイクロm程度）は2本の鞭毛を持ち、海中を泳ぐことができるので特に「遊走子（ゆうそうし）」と呼ばれる。