Where does “日本水仙” come from?

日本水仙 (Japanese) comes from Japanese 日本, from Japanese 日, from Old Japanese 日, from Proto-Japonic *pi — day, sun.

日本水仙 (Japanese): bunch-flowered narcissus (Narcissus tazetta)

Definitions

日本水仙 traces back through two separate lines of ancestry.

Step	Language	Word	Meaning
1	Japanese	日本	{{l\|en\|Japan}}; Japan
2	Japanese	日	Sunday
3	Old Japanese	日	the sun; sunlight, sunshine; daytime, daylight
4	Proto-Japonic	*pi	day, sun

Step	Language	Word	Meaning
1	Japanese	水仙	narcissus
2	Chinese	水仙	paperwhite; Chinese sacred lily; narcissus; Shui...