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.
This beautiful species, entirely aquatic, is found to-day in the North Temperate Zone in Europe, N. and W. Asia, N.W. India. It is unknown in early plant beds. In Great Britain it is absent in Cornwall in the Peninsula province, but grows throughout the Channel, Thames, Anglia, and Severn provinces; in S. Wales only in Glamorgan, Brecon, and Pembroke; in N. Wales Carnarvon, Flint, Anglesea; throughout the Trent, Mersey, and Humber provinces; in Durham only in the Tyne province; in Scotland only in Mid and E. Perth. Elsewhere it ranges from York and Durham to the South Coast. It is naturalized in Scotland, rare in Ireland.
The Flowering Rush is one of the pictures of aquatic vegetation, which rises up in the mind's eye in recalling its main characteristics, as obtained from the point of view of the most beautiful species. It grows in canals, rivers, brooks, streams, and also in ponds and pools indifferently, in the reed swamp.
Like many other aquatic plants, the aerial stem is a scape with many sword-shaped, long leaves surrounding it, and giving it a grasslike habit. The leaves are 3-sided, spongy, twisted, and very sharp, hence the first Greek name. The base of the stem is reddish, like the flower-stalks also. The leaves are sheathed at the base.
Photo. H. Irving - Flowering Rush (Butomus Umbellatus, L.)
The scape is smooth, round, bearing a single umbel of large numerous flowers (20-30 in an umbel), rose-colour, red, purple, the perianth-segments oblong at first with 4 grooves, then more or less heart-shaped. The bracts have a membranous margin. The involucre is in threes, the corolla consists of 6 petals, and there are 9 stamens, 6 pistils, and later 6 capsules.
Flowering Rush is 2-3 ft. high. The flowers may be sought in June and July. The plant is a herbaceous perennial, propagated by division.
The flowers, which are on long stalks, forming a flattish umbel, are proterandrous, the anthers ripening first, the stigma soon after.1 There are 9 stamens, which are hypogynous, 6 in pairs, 3 opposite the inner segments of the perianth. The anther-stalks are awl-shaped, and the anthers are fixed by the base. The styles are short, and the stigmas stalkless.
The follicle contains many seeds, which fall, when the stem is swayed by the wind, into the water, and are so dispersed.
This handsome plant is aquatic, growing in lowland areas, with peat-loving or clay-loving plants.
Butomus, Theophrastus, is from the Greek bous and temno, because the leaves cut the mouths of cattle; and the second Latin name refers to the umbellate inflorescence.
This plant is called Flowering Rush, Water Gladiole. Gerarde says of it: "The water-gladiole or grassie-rush is of all others the fairest and most pleasant to behold and serveth very well for the decking and trimming up of houses, because of the beautie and braverie thereof ".
Essential Specific Characters:-316. Butomus umbellatus, L. - Scape radical, leaves radical, triangular, long, slender, flowers in umbels, rose colour with scarious bracts.