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 glazioviana / Oomatsuyoigusa オオマツヨイグサ

Oenothera glazioviana, a biennial herb introduced from Europe, grows wild in various districts, seasides, or riversides, rising to 0.8-1.5m in height. Stems are with stiff hairs, the bases of which swell and turn dark red. Leaves are 6-15cm long, 2-4cm wide, ovate-like lanceolate, with tips pointed and margins having shallow, wavy serrations. Yellow flowers, 6-8cm in diameter, singly set themselves at the axils with four broad petals. Bloom time: July-September.