Arisaema japonicum Blume

Family: Araceae
English: Jack-in-the-Pulpit sp.
Japanese: マムシグサ [Mamushigusa]

It seems like everyone has an opinion about this flowers found throughout Japan. Some people find it repulsive because of the pattern on the stem remiscent of the Japanese pit-viper, its habit of changing sex, or its poison, but other people are attracted to the cobra-like spathe and cob of red berries. For more about all that, I did a blogpost: http://yakushimalife.blogspot.com/2014/04/arisaema-serratum-toxic-sex-changing.html.

References:
九州野山の花 片野田逸朗,2004：南方新社
米倉浩司・梶田忠 (2003-)　「BG Plants 和名－学名インデックス」（YList），http://ylist.info（ 2019年8月13日）
http://yakushimalife.blogspot.jp/2014/04/arisaema-serratum-toxic-sex-changing.html