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.
As one of the Arctic plants, addicted to an aquatic habitat, one might expect to find this in the Glacial plant-beds, and it is found in Preglacial, Interglacial, Late Glacial, and Neolithic deposits. It is found to-day in the North Temperate Zone generally, and in the Himalayas and Australia. In Great Britain, Water Plantain does not grow in Cardigan, Stirling, Mid Perth, Westerness, Alain Argyle, N. Ebudes, N. Highlands, except Ross and Northern Isles. It is found in Ireland and the Channel Islands.
Water Plantain is an aquatic plant, which becomes terrestrial under certain exigencies when a piece of water is silted up. It is impartial to still or running water, growing in ponds, pools, and lakes, where it forms at the margin dense clumps, tall and graceful. It is less frequent in running water, streams, and rivers. It grows in the reed swamp.
The aerial flowering stems, which are scapes, with broadly branching panicles, make an imposing show in the pool or lake. The leaves are all radical, stalked, the leaf-stalks channelled and sheathed, the leaves oblong, lance-shaped, acute, veined, and when floating they are linear. The second Latin name indicates a resemblance between the leaves of the Plantain (hence also the English name) and this plant.
The scape bearing the flowers is three-angled, and swollen or fleshy below. The white or pink flowers have a yellow claw, and are borne in panicles with branches in whorls, compound, smooth, naked. The numerous carpels are flattened at the side, blunt, with the style, ventral, below the top of the carpel. They are twice as long as the ovary, and the stigmas are simple. The perianth consists of 6 segments.
Water Plantain is 18 in. to 2 ft. high. The flowers bloom in June and July. The plant is a perennial, propagated by division.
The white or pink flowers in a loose pyramidal panicle are yellow at the base, forming a disk 10 mm. in diameter. The anthers and stigma are ripe together. If the insect alights in the middle it touches the stigma first, then the anthers, or else if it alights on the petals it then touches the anthers covered with pollen with different parts of the body, as well as the stigma. It is more likely to cross- than self-pollinate the plant, especially when alighting in the middle, and when alighting on the petals the former result is also more probable from the relative position of the parts. The anthers open externally, and are directed upwards and outwards. Honey half-concealed is secreted in 12 drops at the base of the stamens in the ring formed by the anther-stalks, and one opposite each anther-stalk, and one in each interval.
The flies make a tour of these drops and get thoroughly dusted with pollen in the process. The plant is visited by flies, Eristalis sepulchra-lis, Syritta pipiens, Ascia podagrica, Melanostoma mellina, Melithreptus.
The carpels when ripe fall to the ground or water and are so dispersed.
This handsome plant is aquatic or terrestrial. It grows on sandy loam or silt, alluvium, etc.
A fungus, Doassansia alismalis, is found to attack it. Two beetles, Donacia menyanthidis, Hydrono-mus alismalis, three moths, The Dog's Tooth (Hadena suasa), Gold Spot (Plusia festucae), Tortrix viburnana, are found on it.
Alisma, Pliny, is ultimately connected with the Greek hals, salt, and the second Latin name means water plantain, Plantago being a name given by Pliny.
This plant is called Deil's Spoons, Great Thrumwort. It causes blisters applied externally, and is bitter. It is injurious to cattle.
Essential Specific Characters:314. Alisma Plantago-aquatica, L. - Scape tall, branched, leaves radical, erect, lanceolate, petiolate, flowers pink in whorls, fruit compressed.
Photo. J. H. Crabtree - Water Plantain (Alisma Plantago-aquatica, L.)