This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flowers - Very small and numerous, white, or pale pink, whorled in bracted clusters forming a large, loose panicle 6 to 15 in. long on a usually solitary scape 1/2 to 3 ft. high. Calyx of 3 sepals; corolla of 3 deciduous petals; 6 or more stamens; many carpels in a ring on a small flat receptacle. Leaves: Erect or floating, oblong or ovate, with several ribs, or lance-shaped or grass-like, petioled, all from root.
Per/erred Habitat - Shallow water, mud, marshes.
Flowering Season - June - September.
Distribution - North America, Europe, Asia.
Unlike its far more showy, decorative cousin the arrow-head, this wee-blossomed plant, whose misty white panicles rise with compensating generosity the world around, bears only perfect, regular flowers. Twelve infinitesimal drops of nectar, secreted in a fleshy ring around the centre, are eagerly sought by flies. As the anthers point obliquely outward and away from the stigmas, an incoming fly, bearing pollen on his under side, usually alights in the centre, and leaves some of the vitalizing dust just where it is most needed. But a "fly starting from a petal," says Muller, "usually applies its tongue to the nectar-drops one by one, and after each it strokes an anther with its labellae; in so doing it may bring various parts of its body in contact with the anthers. As a rule, however, the parts which come in contact with the anthers are not those which come in contact with the stigmas in the same flower." Any plant that lives in shallow water, which may dry up as summer advances, is under special necessity to produce an extra quantity of cross-fertilized seed to guard against extinction during drought. For the same reason it bears several kinds of leaves adapted to its environment: broad ones that spread their surfaces to the sunshine, and long grass-like ones to glide through currents of water that would tear those of any other shape (see p. 155). What diversity of leaf-form and structure we meet daily, and yet how very little does the wisest man of science understand of the reasons underlying such marvellous adaptability!