This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
1. Arrowhead (Sagittaria sagittifolia, L.). 2. Flowering Rush (Butomus umbellalus, L.). 3. Bulrush (Scirpus lacustris, L.). 4. Wood Club Rush (Sarpus sylvaticus, L.). 5. Reed (Phragmites communis, Trin.).
Photo. L. R. J. Horn - Arrow-Head (Sagittaria sagittijolia, L.)
Arrow-head is aquatic, and a peat- or clay-loving plant.
This choice plant is infested by two fungi, Aecidium incarceratun and Doassansia sagittariae. A beetle, Galeruca sagittariae, is found on it.
Sagittaria, Lobel, is from the Latin sagitta, an arrow, and the second Latin name also refers to the arrow-shaped leaves.
Arrow-head is called Adder's Tongue, Water Archer, Arrow-head. As to the second name Gerarde says, "Because it is good to pull out arrows" by Doctrine of Signatures! and as to the last he says, "Hath large and long leaves, in shape like the signe Sagittarius, or rather like a bearded broad arrowe-heade".
The rhizome is bulbous, and has been used as an article of food in China, and here it is cultivated.
There are 3 types of leaf. The submerged type is ribbon-like, the floating leaves are oblong to heart-shaped, short, the erect, non-submerged aerial leaves are arrow-shaped. The first are extremely thin, and the chlorophyll granules are arranged according to the state of the light; they are flat and wave about in the water.
Essential Specific Characters:315. Sagittaria sagittifolia, L. - Leaves on long petioles, hastate, erect, submerged petioles linear, flowers white, in whorls of 3.