The flower Akebia quinata is native to Japan and has edible fruit and its petals grow in a beautiful magenta which inspires the color of the ink. Akebi also has a prominent green sheen that can be seen in any nib size.
The Sailor Manyo series is based off of the Man'yōshū, a Collection of Ten Thousand Leaves. It is the oldest and one of the most revered collections of classical Japanese poems ever compiled. A great number of the poems mention various beautiful flowers from Japan.