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 grandis / Oobanakomatsuyoigusa オオバナコマツヨイグサ

Oenothera grandis, a biennial herb native to North America, grows wild along seashores, riverbanks, and in open spaces in western Japan. Stems with many vellus hairs branch at the bases, crawling on the ground; upper parts ascend obliquely upward to grow to 20-50cm in height. Leaves are oblanceolate and 2-7cm long; some are cleft in half or undulated on margins. Flowers are light yellow, measure 4cm in diameter, and have four petals. Bloom time: May-October.