THE Arrowhead is a very decorative and common, mud-loving, white-flowered aquatic perennial, blooming from July to September, in shallow water along the margins of slow streams, ponds, and marshes. The exceedingly variable leaves are generally arrow-shaped, sometimes sharp and narrow, or again blunt and broad. They are thick, spongy, and rubbery, and have long stems. Others, which are entirely submerged under the water, are long and grass-like. The many-angled, milky-juiced, flowering stalk is either stout or slender, and grows from a few inches to several feet in height. The flowers have three prominent, rounded, spreading, white petals with either a central cluster of golden yellow stamens or a large, green pistil. They are of two sorts, male and female, and may or may not occur together on the same plant. In the latter case, the pretty male, or yellow-centred, stamen-bearing flowers are borne on the upper part of the stalk, while the female or green-centred, pistil-bearing flowers occur below them. They are arranged in whorls of three, on short stems, at regular distances along the stalk. The calyx has three green parts. The Arrowhead ranges from Mexico far into the British Possessions, and from the Atlantic to the Pacific. S. pubescens is a robust, broad leaved variety, with a shorter calyx, and is more or less hairy. It is found from Ontario to New Jersey, Florida and Alabama.