Abstract

Members of the genus Arisaema (Araceae) are perennial understory herbs that were traditionally used in medieval Japan in the treatment of flesh wounds resulting from warfare to prevent tetanus. This study aimed to elucidate the distribution of Arisaema in the ruins of fortresses dating from the medieval period in Japan. Two hypotheses were tested: that Arisaema are commonly found in the ruins of fortresses in central Japan and that Arisaema grows more intensively at military sites than in surrounding areas. A. serratum var. serratum, A. thunbergii subsp. urashima, A. yamatense subsp. yamatense, A. kishidae, and A. tosaense were observed at 19 of the 27 fortresses examined. A census conducted along the major traditional routes in northwestern Nara Prefecture revealed that Arisaema was clumped more intensely at military sites, and fewer plants were observed in the surrounding areas. These findings indicate a strong association between Arisaema and military sites. Climatic conditions and modification of soil microclimate resulting from fortress construction could not adequately explain this association. However, this association, combined with the historical importance of Arisaema in the treatment of wounds, implies that Arisaema plants found in the fortresses are historical remnants of plants used to treat warriors and commanders in medieval Japan.

Key words: Arisaema, commander, ethnobotany, medieval Japan, military, tetanus.