Hyssop loosestrife

Lythrum hyssopifolia

Leaves:

Mainly alternate, some opposite.
Stipules - Absent.
Petiole - Short or none.
Blade - Dark green, oblong, 5-40 mm long by 1.5-6 mm wide. Tip rounded. to flat. Sides convex to almost parallel. Base tapered. Surface hairless.

Flowers:

Sepals - -4-6, green, broad, erect, membranous, < 1mm long and narrowly triangular with 4-6 longer, green, lance shaped appendages.
Petals - 4-6, pink, red-blue or purplish, 1-2 mm long, about half as long as the receptacle.