Species in the genus Oenothera:

Oenothera biennis / Mematsuyoigusa
Oenothera glazioviana / Oomatsuyoigusa
Oenothera grandis / Oobanakomatsuyoigusa
Oenothera rosea / Akabanayuugeshou
Oenothera speciosa / Hiruzakitsukimisou
　

Oenothera speciosa / Hiruzakitsukimisou ヒルザキツキミソウ

Oenothera speciosa, a perennial herb originating in North America, partly grows wild in western Japan; stems with many short hairs growing to 30-60cm in height. Leaves are alternate, 5-7cm long, in a linear-oblanceolate shape, with shallow margins. White or light red flowers measure 5cm in diameter; buds face downward but upward when open. Petals are in the shape of a broad-obovate, with bases tinging yellow. Bloom time: May-August.