Notes For Reference:-　

Species, Varieties, or Forms 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 native to North America, also grows wild in western Japan. Stems with many short hairs growing to 30-60cm in height. Leaves are alternate, 5-7cm long, linear-oblanceolate, with shallow margins. White or light red flowers measure 5cm in diameter; Buds face downward but open upward. Petals are in the shape of a broad-obovate, with bases tinging yellow. Bloom time: May-August.