Japanese bindweed; Calystegia japonica
A flowering plant native to Japan, often found in fields and roadsides. The name literally means 'daytime face' because the flowers bloom during the day.
Japanese bindweed was blooming by the roadside.
housewife having an affair while her husband is at work
Katakana spelling is common for plant names; usually written in kana.
Kanji spelling is rare; the plant is normally written in kana.
Hiragana spelling, also used.
Formed from 昼 and 顔, with the name contrasting the daytime-blooming flower with 朝顔, the morning glory.